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James W. Thomas - One of the best experts on this subject based on the ideXlab platform.
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Genes located in a chromosomal inversion are correlated with territorial song in White-Throated Sparrows
Genes Brain and Behavior, 2015Co-Authors: Wendy M. Zinzow-kramer, Brent M. Horton, James W. Thomas, Elaina M. Tuttle, Clifton D. Mckee, Justin M. Michaud, Gregory K. Tharp, Soojin V. Yi, Donna L. ManeyAbstract:The genome of the White-Throated Sparrow (Zonotrichia albicollis) contains an inversion polymorphism on chromosome 2 that is linked to predictable variation in a suite of phenotypic traits including plumage color, aggression, and parental behavior. Differences in gene expression between the two color morphs, which represent the two common inversion genotypes (ZAL2/ZAL2 and ZAL2/ZAL2m), are therefore of potential interest toward understanding the molecular underpinnings of these phenotypes. To identify genes that are differentially expressed between the two morphs and correlated with behavior, we quantified both behavior and brain gene expression in a population of free-living White-Throated Sparrows. We quantified behavioral responses to simulated territorial intrusions (STIs) early during the breeding season. In the same birds, we then performed a transcriptome-wide analysis of gene expression in two regions, the medial amygdala and hypothalamus. Both regions are part of a ‘social behavior network’, which is rich in steroid hormone receptors and previously linked with territorial behavior. Using network analyses, we identified modules of genes that were correlated with both morph and STI-induced singing behavior. The majority of these genes were located within the inversion, demonstrating the profound effect the inversion has on the expression of genes captured by the rearrangement. Gene pathway analyses revealed that in the medial amygdala, the most prominent pathways were those related to steroid hormone receptor activity. Within these pathways, the only gene encoding such a receptor was ESR1 (estrogen receptor alpha). Our results thus suggest that ESR1 and related genes are important for behavioral differences between the morphs.
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Behavioral Characterization of a White-Throated Sparrow Homozygous for the ZAL2m Chromosomal Rearrangement
Behavior Genetics, 2012Co-Authors: Brent M. Horton, James W. Thomas, Yuchen Hu, Christa Lese Martin, Brian Bunke, Beth Matthews, Ignacio T. Moore, Donna L. ManeyAbstract:The White-Throated Sparrow is rapidly becoming an important model in the genetics of social behavior because of a chromosomal rearrangement that segregates with a behavioral phenotype. Within a population, 50 % of individuals are heterozygous for a rearranged chromosome 2 (ZAL2m). These birds sing more and are more aggressive than the other 50 %, who lack the rearrangement. A disassortative mating system, in which heterozygotes almost never interbreed, ensures that ZAL2m/2m homozygotes are extremely rare. Here, we provide the first systematic characterization of such a homozygote, a hatch-year female. Her plumage was atypical of her age and sex, resembling that of an adult male. She was extremely vocal and aggressive, dominating her opponents in behavioral tests. Her phenotype was thus an exaggerated version of a typical ZAL2/2m heterozygote, supporting the hypothesis that alleles inside the ZAL2m rearrangement confer high aggression and further emphasizing this species’ value as a model of social behavior.
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Contrasting population genetic patterns within the White-Throated Sparrow genome (Zonotrichia albicollis)
BMC Genetics, 2010Co-Authors: Lynn Y. Huynh, Donna L. Maney, James W. ThomasAbstract:The level of nucleotide diversity observed across the genome is positively correlated with the local rate of recombination. Avian karyotypes are typified by large variation in chromosome size and the rate of recombination in birds has been shown to be negatively correlated with chromosome size. It has thus been predicted that nucleotide diversity is negatively correlated with chromosome size in aves. However, there is limited empirical evidence to support this prediction. Here we sequenced 27 autosomal and 12 sex chromosome-linked loci in the White-Throated Sparrow (Zonotrichia albicollis) to quantify and compare patterns of recombination, linkage disequilibrium (LD), and genetic diversity across the genome of this North American songbird. Genetic diversity on the autosomes varied up to 8-fold, with the lowest diversity observed on the macrochromosomes and the highest diversity on the microchromosomes. Genetic diversity on the sex chromosomes was reduced compared to the autosomes, the most extreme difference being a ~300-fold difference between the W chromosome and the microchromosomes. LD and population structure associated with a common inversion polymorphism (ZAL2/2m) in this species were found to be atypical compared to other macrochromosomes, and nucleotide diversity within this inversion on the two chromosome arrangements was more similar to that observed on the Z chromosome. A negative correlation between nucleotide diversity and autosome size was observed in the White-Throated Sparrow genome, as well as low levels of diversity on the sex chromosomes comparable to those reported in other birds. The population structure and extended LD associated with the ZAL2/2m chromosomal polymorphism are exceptional compared to the rest of the White-Throated Sparrow genome.
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A W-linked palindrome and gene conversion in New World Sparrows and blackbirds
Chromosome Research, 2010Co-Authors: Jamie K. Davis, Pamela J. Thomas, James W. ThomasAbstract:A hallmark feature of the male-specific region of the human Y chromosome is the presence of large and near-identical palindromes. These palindromes are maintained in a state of near identity via gene conversion between the arms of the palindrome, and both neutral and selection-based theories have been proposed to explain their enrichment on the human Y and X chromosomes. While those proposed theories would be applicable to sex chromosomes in other species, it has not been established whether near-identical palindromes are a common feature of sex chromosomes in a broader range of taxa, including other tetrapods. Here, we report the genomic sequencing and features of a 279-kb region of the non-recombining portion of the W chromosome spanning the CHD1W locus in a New World Sparrow, the White-Throated Sparrow ( Zonotrichia albicollis ), and the corresponding region on the Z chromosome. As has been observed for other Y and W chromosomes, we detected a high repetitive element content (51%) and low gene content on the White-Throated Sparrow W chromosome. In addition, we identified a 22-kb near-identical (>99%) palindrome on the W chromosome that flanks the 5′ end of the CHD1W gene. Signatures of gene conversion were readily detected between the arms of this palindrome, as was the presence of this palindrome in other New World Sparrows and blackbirds. Near-identical palindromes are therefore present on the avian W chromosome and may persist due to the same forces proposed for the enrichment of these elements on the human sex chromosomes.
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Chromosome-wide linkage disequilibrium caused by an inversion polymorphism in the White-Throated Sparrow ( Zonotrichia albicollis )
Heredity, 2010Co-Authors: Lynn Y. Huynh, Donna L. Maney, James W. ThomasAbstract:Chromosomal inversions have been of long-standing interest to geneticists because they are capable of suppressing recombination and facilitating the formation of adaptive gene complexes. An exceptional inversion polymorphism (ZAL2m) in the White-Throated Sparrow (Zonotrichia albicollis) is linked to variation in plumage, social behavior and mate choice, and is maintained in the population by negative assortative mating. The ZAL2m polymorphism is a complex inversion spanning >100 Mb and has been proposed to be a strong suppressor of recombination, as well as a potential model for studying neo-sex chromosome evolution. To quantify and evaluate these features of the ZAL2m polymorphism, we generated sequence from 8 ZAL2m and 16 ZAL2 chromosomes at 58 loci inside and 4 loci outside the inversion. Inside the inversion we found that recombination was completely suppressed between ZAL2 and ZAL2m, resulting in uniformly high levels of genetic differentiation (FST=0.94), the formation of two distinct haplotype groups representing the alternate chromosome arrangements and extensive linkage disequilibrium spanning ∼104 Mb within the inversion, whereas gene flow was not suppressed outside the inversion. Finally, although ZAL2m homozygotes are exceedingly rare in the population, occurring at a frequency of
Elaina M. Tuttle - One of the best experts on this subject based on the ideXlab platform.
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Quantitative color variation within and across morphs of the polymorphic White-Throated Sparrow
The Auk, 2020Co-Authors: Nathan A. Rathbun, Rusty A. Gonser, Andrea S. Grunst, Melissa L. Grunst, Joanna K. Hubbard, Rebecca J. Safran, Elaina M. TuttleAbstract:ABSTRACT Coloration has evolved to serve diverse functions, including communication. In species with discrete color polymorphisms, the extent to which color variation exists within morphs and communicates multiple messages often remains unclear. We employed reflectance spectrometry to study variation in coloration in the dimorphic White-Throated Sparrow (Zonotrichia albicollis), which exhibits a “white” and “tan” morph in both sexes. We explored whether distinct color traits distinguish between morph and sex classes, and whether color variation exists within classes that might reflect differences in individual quality. Further, we asked whether sexual dichromatism is more pronounced in the white morph, in which males display greater promiscuity and aggression and, thus, may be under stronger sexual selection for conspicuous coloration. Distinct aspects of crown plumage coloration differentiated the two morphs versus the two sexes and multiple types of coloration were associated with a morph, suggesting bo...
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Negative-Assortative Mating in the White-Throated Sparrow.
Journal of Heredity, 2017Co-Authors: Philip W. Hedrick, Elaina M. Tuttle, Rusty A. GonserAbstract:: Nonrandom mating based on phenotype has been observed in a number of organisms, but a very high proportion of these examples are of assortative mating. The strongest example of negative-assortative mating is for white-striped versus tan-striped crown in the White-Throated Sparrow, where about 98% of the observed pairings (mated pairs or social pairs) are between mates with different phenotypes and the correlation between mating types is -0.964. Although nonrandom mating has been explored theoretically for decades, these models have generally not focused on specific well-documented examples. Here we have developed a model to investigate the dynamics and equilibrium of this iconic example. The observed pattern of mating appears to be the result of 96% negative-assortative mating and a 17% advantage of W (white) male × T (tan) female matings compared to the reciprocal T male × W female matings. The equilibrium heterozygosity given these values is 0.500, very close to the 0.501 observed in our large sample of pairings, and this heterozygosity has been maintained for the 29 years from 1988 to 2016. In addition, the equilibrium frequency of 2m inversion determining the white-striped phenotype has been maintained at a frequency very close to its equilibrium frequency of 0.25. Overall, this model demonstrates how evolutionary genetic models can be used to understand negative-assortative mating.
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Genes located in a chromosomal inversion are correlated with territorial song in White-Throated Sparrows
Genes Brain and Behavior, 2015Co-Authors: Wendy M. Zinzow-kramer, Brent M. Horton, James W. Thomas, Elaina M. Tuttle, Clifton D. Mckee, Justin M. Michaud, Gregory K. Tharp, Soojin V. Yi, Donna L. ManeyAbstract:The genome of the White-Throated Sparrow (Zonotrichia albicollis) contains an inversion polymorphism on chromosome 2 that is linked to predictable variation in a suite of phenotypic traits including plumage color, aggression, and parental behavior. Differences in gene expression between the two color morphs, which represent the two common inversion genotypes (ZAL2/ZAL2 and ZAL2/ZAL2m), are therefore of potential interest toward understanding the molecular underpinnings of these phenotypes. To identify genes that are differentially expressed between the two morphs and correlated with behavior, we quantified both behavior and brain gene expression in a population of free-living White-Throated Sparrows. We quantified behavioral responses to simulated territorial intrusions (STIs) early during the breeding season. In the same birds, we then performed a transcriptome-wide analysis of gene expression in two regions, the medial amygdala and hypothalamus. Both regions are part of a ‘social behavior network’, which is rich in steroid hormone receptors and previously linked with territorial behavior. Using network analyses, we identified modules of genes that were correlated with both morph and STI-induced singing behavior. The majority of these genes were located within the inversion, demonstrating the profound effect the inversion has on the expression of genes captured by the rearrangement. Gene pathway analyses revealed that in the medial amygdala, the most prominent pathways were those related to steroid hormone receptor activity. Within these pathways, the only gene encoding such a receptor was ESR1 (estrogen receptor alpha). Our results thus suggest that ESR1 and related genes are important for behavioral differences between the morphs.
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Genetic Verification of Dizygotic Twin Embryos in the White-Throated Sparrow (Zonotrichia albicollis)
The Wilson Journal of Ornithology, 2015Co-Authors: Adam M. Betuel, Elaina M. Tuttle, Rusty A. GonserAbstract:The incidence of twinning in avian species is a phenomenon that has been rarely encoun- tered. A number of domestic species have been shown to produce twins but in very low numbers. In wild populations, only 14 species have been documented producing twin embryos or nestlings. Despite this, it has been postulated that birds are just as likely as any other vertebrate to produce twin offspring. Here we describe the discovery of dizygotic twins in a long-term study of breeding ecology in the White-Throated Sparrow (Zonotrichia albicollis). The twin containing egg was 12% heavier than the mean and had a mass greater than 94% of eggs collected. The twin containing egg was wider and longer than the majority of other eggs collected during 2010 but still within the expected range for White-Throated Sparrows. Genetic analysis demon- strated that the twin embryos were full siblings but of different morph and sex. This is the first documented case of twinning in our study site out of over 2000 samples over 25 years of study, and likely the first confirmed case of twinning in this species. Received 30 June 2014. Accepted 27 March 2015.
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Variation in Preen Oil Composition Pertaining to Season, Sex, and Genotype in the Polymorphic White-Throated Sparrow
Journal of Chemical Ecology, 2014Co-Authors: Elaina M. Tuttle, Peter J. Sebastian, Amanda L. Posto, Helena A. Soini, Milos V. Novotny, Rusty A. GonserAbstract:Evidence for the the ability of birds to detect olfactory signals is now well documented, yet it remains unclear whether birds secrete chemicals that can be used as social cues. A potential source of chemical cues in birds is the secretion from the uropygial gland, or preen gland, which is thought to waterproof, maintain, and protect feathers from ectoparasites. However, it is possible that preen oil also may be used for individual recognition, mate choice, and signalling social/sexual status. If preen oil secretions can be used as socio-olfactory signals, we should be able to identify the volatile components that could make the secretions more detectable, determine the seasonality of these secretions, and determine whether olfactory signals differ among relevant social groups. We examined the seasonal differences in volatile compounds of the preen oil of captive White-Throated Sparrows, Zonotrichia albicollis. This species is polymorphic and has genetically determined morphs that occur in both sexes. Mating is almost exclusively disassortative with respect to morph, suggesting strong mate choice. By sampling the preen oil from captive birds in breeding and non-breeding conditions, we identified candidate chemical signals that varied according to season, sex, morph, and species. Linear alcohols with a 10–18 carbon chains, as well as methyl ketones and carboxylic acids, were the most abundant volatile compounds. Both the variety and abundances of some of these compounds were different between the sexes and morphs, with one morph secreting more volatile compounds in the non-breeding season than the other. In addition, 12 compounds were seasonally elevated in amount, and were secreted in high amounts in males. Finally, we found that preen oil signatures tended to be species-specific, with White-Throated Sparrows differing from the closely related Junco in the abundances and/or prevalence of at least three compounds. Our data suggest roles for preen oil secretions and avian olfaction in both non-social as well as social interactions.
Donna L. Maney - One of the best experts on this subject based on the ideXlab platform.
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Rapid effects of estradiol on aggression depend on genotype in a species with an estrogen receptor polymorphism.
Hormones and Behavior, 2018Co-Authors: Jennifer R. Merritt, Kiran K Soma, Donald R. Williams, Matthew T. Davis, Cecilia Jalabert, Timothy J. Libecap, Donna L. ManeyAbstract:Abstract The White-Throated Sparrow (Zonotrichia albicollis) represents a powerful model in behavioral neuroendocrinology because it occurs in two plumage morphs that differ with respect to steroid-dependent social behaviors. Birds of the white-striped (WS) morph engage in more territorial aggression than do birds of the tan-striped (TS) morph, and the TS birds engage in more parenting behavior. This behavioral polymorphism is caused by a chromosomal inversion that has captured many genes, including estrogen receptor alpha (ERα). In this study, we tested the hypothesis that morph differences in aggression might be explained by differential sensitivity to estradiol (E2). We administered E2 non-invasively to non-breeding White-Throated Sparrows and quantified aggression toward a conspecific 10 min later. E2 administration rapidly increased aggression in WS birds but not TS birds, consistent with our hypothesis that differential sensitivity to E2 may at least partially explain morph differences in aggression. To query the site of E2 action in the brain, we administered E2 and quantified Egr-1 expression in brain regions in which expression of ERα is known to differ between the morphs. E2 treatment decreased Egr-1 immunoreactivity in nucleus taeniae of the amygdala, but this effect did not depend on morph. Overall, our results support a role for differential effects of E2 on aggression in the two morphs, but more research will be needed to determine the neuroanatomical site of action.
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Genes located in a chromosomal inversion are correlated with territorial song in White-Throated Sparrows
Genes Brain and Behavior, 2015Co-Authors: Wendy M. Zinzow-kramer, Brent M. Horton, James W. Thomas, Elaina M. Tuttle, Clifton D. Mckee, Justin M. Michaud, Gregory K. Tharp, Soojin V. Yi, Donna L. ManeyAbstract:The genome of the White-Throated Sparrow (Zonotrichia albicollis) contains an inversion polymorphism on chromosome 2 that is linked to predictable variation in a suite of phenotypic traits including plumage color, aggression, and parental behavior. Differences in gene expression between the two color morphs, which represent the two common inversion genotypes (ZAL2/ZAL2 and ZAL2/ZAL2m), are therefore of potential interest toward understanding the molecular underpinnings of these phenotypes. To identify genes that are differentially expressed between the two morphs and correlated with behavior, we quantified both behavior and brain gene expression in a population of free-living White-Throated Sparrows. We quantified behavioral responses to simulated territorial intrusions (STIs) early during the breeding season. In the same birds, we then performed a transcriptome-wide analysis of gene expression in two regions, the medial amygdala and hypothalamus. Both regions are part of a ‘social behavior network’, which is rich in steroid hormone receptors and previously linked with territorial behavior. Using network analyses, we identified modules of genes that were correlated with both morph and STI-induced singing behavior. The majority of these genes were located within the inversion, demonstrating the profound effect the inversion has on the expression of genes captured by the rearrangement. Gene pathway analyses revealed that in the medial amygdala, the most prominent pathways were those related to steroid hormone receptor activity. Within these pathways, the only gene encoding such a receptor was ESR1 (estrogen receptor alpha). Our results thus suggest that ESR1 and related genes are important for behavioral differences between the morphs.
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Evaluation of reference genes for quantitative real-time PCR in the brain, pituitary, and gonads of songbirds.
Hormones and Behavior, 2014Co-Authors: Wendy M. Zinzow-kramer, Brent M. Horton, Donna L. ManeyAbstract:Abstract Quantitative real-time PCR (qPCR) is becoming a popular tool for the quantification of gene expression in the brain and endocrine tissues of songbirds. Accurate analysis of qPCR data relies on the selection of appropriate reference genes for normalization, yet few papers on songbirds contain evidence of reference gene validation. Here, we evaluated the expression of ten potential reference genes (18S, ACTB, GAPDH, HMBS, HPRT, PPIA, RPL4, RPL32, TFRC, and UBC) in brain, pituitary, ovary, and testis in two species of songbirds: zebra finch and White-Throated Sparrow. We used two algorithms, geNorm and NormFinder, to assess the stability of these reference genes in our samples. We found that the suitability of some of the most popular reference genes for target gene normalization in mammals, such as 18S, depended highly on tissue type. Thus, they are not the best choices for brain and gonad in these songbirds. In contrast, we identified alternative genes, such as HPRT, RPL4 and PPIA, that were highly stable in brain, pituitary, and gonad in these species. Our results suggest that the validation of reference genes in mammals does not necessarily extrapolate to other taxonomic groups. For researchers wishing to identify and evaluate suitable reference genes for qPCR in songbirds, our results should serve as a starting point and should help increase the power and utility of songbird models in behavioral neuroendocrinology.
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Behavioral Characterization of a White-Throated Sparrow Homozygous for the ZAL2m Chromosomal Rearrangement
Behavior Genetics, 2012Co-Authors: Brent M. Horton, James W. Thomas, Yuchen Hu, Christa Lese Martin, Brian Bunke, Beth Matthews, Ignacio T. Moore, Donna L. ManeyAbstract:The White-Throated Sparrow is rapidly becoming an important model in the genetics of social behavior because of a chromosomal rearrangement that segregates with a behavioral phenotype. Within a population, 50 % of individuals are heterozygous for a rearranged chromosome 2 (ZAL2m). These birds sing more and are more aggressive than the other 50 %, who lack the rearrangement. A disassortative mating system, in which heterozygotes almost never interbreed, ensures that ZAL2m/2m homozygotes are extremely rare. Here, we provide the first systematic characterization of such a homozygote, a hatch-year female. Her plumage was atypical of her age and sex, resembling that of an adult male. She was extremely vocal and aggressive, dominating her opponents in behavioral tests. Her phenotype was thus an exaggerated version of a typical ZAL2/2m heterozygote, supporting the hypothesis that alleles inside the ZAL2m rearrangement confer high aggression and further emphasizing this species’ value as a model of social behavior.
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Contrasting population genetic patterns within the White-Throated Sparrow genome (Zonotrichia albicollis)
BMC Genetics, 2010Co-Authors: Lynn Y. Huynh, Donna L. Maney, James W. ThomasAbstract:The level of nucleotide diversity observed across the genome is positively correlated with the local rate of recombination. Avian karyotypes are typified by large variation in chromosome size and the rate of recombination in birds has been shown to be negatively correlated with chromosome size. It has thus been predicted that nucleotide diversity is negatively correlated with chromosome size in aves. However, there is limited empirical evidence to support this prediction. Here we sequenced 27 autosomal and 12 sex chromosome-linked loci in the White-Throated Sparrow (Zonotrichia albicollis) to quantify and compare patterns of recombination, linkage disequilibrium (LD), and genetic diversity across the genome of this North American songbird. Genetic diversity on the autosomes varied up to 8-fold, with the lowest diversity observed on the macrochromosomes and the highest diversity on the microchromosomes. Genetic diversity on the sex chromosomes was reduced compared to the autosomes, the most extreme difference being a ~300-fold difference between the W chromosome and the microchromosomes. LD and population structure associated with a common inversion polymorphism (ZAL2/2m) in this species were found to be atypical compared to other macrochromosomes, and nucleotide diversity within this inversion on the two chromosome arrangements was more similar to that observed on the Z chromosome. A negative correlation between nucleotide diversity and autosome size was observed in the White-Throated Sparrow genome, as well as low levels of diversity on the sex chromosomes comparable to those reported in other birds. The population structure and extended LD associated with the ZAL2/2m chromosomal polymorphism are exceptional compared to the rest of the White-Throated Sparrow genome.
J. Bruce Falls - One of the best experts on this subject based on the ideXlab platform.
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Negative assortative mating in the White-Throated Sparrow, Zonotrichia albicollis : the role of mate choice and intra-sexual competition
Animal Behaviour, 1994Co-Authors: Anne M. Houtman, J. Bruce FallsAbstract:Abstract Abstract. White-Throated Sparrows are dimorphic, mating disassortatively by morph. In laboratory choice trials, females of both morphs preferred tan-striped males when allowed to interact with males (two-way choice), but displayed no preferences when one-way mirrors did not allow stimulus males to interact with them (one-way choice). Males of both morphs displayed significant preferences for white-striped females in one-way choice trials, but not in two-way trials. During within-sex competition trials, white-striped birds were dominant to tan-striped birds of the same sex. These results suggest that negative assortative mating is maintained in part because white-striped females outcompete tan-striped females for access to the preferred tan-striped males. Tan-striped females then pair with the less preferred white-striped males. A three-step process is proposed to account for the high level of negative assortative mating seen in the White-Throated Sparrow.
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Aggressive Performance as a Behavioral Correlate of Plumage Polymorphism in the White-Throated Sparrow (Zonotrichia Albicollis)
Behaviour, 1993Co-Authors: J. Bruce Falls, Jeffrey G. KopachenaAbstract:AbstractMorph and sex-specific differences in aggressive performance were examined in the White-Throated Sparrow. Among the four morph/sex classes, white-striped males had the strongest response to white-striped models and were the most likely to approach and attend song playbacks independently. The slightly weaker responses of tan-striped males and white-striped females were similar to each other. Tan-striped females were the least aggressive. Aggression by white-striped females enabled tan-striped male x white-striped female pairs to perform as well, or better, than white-striped male x tan-striped female pairs. Tan-striped males paired earlier than white-striped males. An increased prevalence of territorial tan-striped males corresponded to the arrival of females on the breeding grounds. The data are consistent with the hypothesis that negative assortative mating benefits tan-striped males through the supplemental aggression of white-striped females. However, the apparent preference of white-striped females for tan-striped males suggests that there are benefits to negative asortative mating other than those that might arise from differences in aggressive performance.
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Re-evaluation of morph-specific variations in parental behavior of the White-Throated Sparrow
The Wilson Journal of Ornithology, 1993Co-Authors: Jeffrey G. Kopachena, J. Bruce FallsAbstract:-We studied White-Throated Sparrows (Zonotrichia albicollis) to determine whether morph-specific variations in parental care are typical of this species and whether the influence of neighbors could account for the occurrence of such variations in some samples but not in others. White-striped males made fewer provisioning trips than did tanstriped females. The provisioning rates of tan-striped males and white-striped females were intermediate. Parental care was not affected by the number of neighbors, neighbor singing, local density, or territory size. White-striped male provisioning was positively correlated with the length of their shared territory boundary and their song rates. These effects are likely due to male condition rather than the influence of neighbors. Such variations in the provisioning behavior of white-striped males could account for the lack of morphic variation found in some samples. Received 29 May 1992, accepted 21 Sept. 1992. During the breeding season, White-Throated Sparrows (Zonotrichia albicollis), possess a discrete plumage polymorphism (white-striped morph, tan-striped morph; Lowther 1961) that is associated with a chromosomal polymorphism (Thorneycroft 1975). This polymorphism is maintained within populations by negative assortative mating. Thus, over 90% of the breeding population consists of two pair types: white-striped males mated with tan-striped females and tan-striped males mated with white-striped females. To understand why polymorphism in the White-Throated Sparrow persists, it is necessary to determine what factors promote negative assortative mating. Knapton and Falls (1983) documented morphic differences in the parental behavior of White-Throated Sparrows. They found that white-striped males made fewer provisioning trips to nestlings than did tan-striped females. Tan-striped males and white-striped females had intermediate provisioning rates and did not differ from each other. These results led Knapton and Falls (1983) to suggest that morphic variations in parental care might favor negative assortative mating. Furthermore, because the overall performance of the two pair types was equivalent, negative assortative mating was viewed as a stable strategy in which neither pair type experienced a reproductive advantage (see also Knapton et al. 1984). A more recent study by Whillans and Falls (1990) failed to find morphic differences in parental care. This latter result casts doubt on the role of Dept. of Zoology, Univ. of Toronto, Toronto, Ontario, Canada, M5S I AI. 2 Present address: Dept. of Biology, Queen's Univ., Kingston, Ontario, Canada, K7L 3N6.
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Postfledging parental care in the White-Throated Sparrow (Zonotrichia albicollis)
Canadian Journal of Zoology, 1993Co-Authors: Jeffrey G. Kopachena, J. Bruce FallsAbstract:We studied parental care in White-Throated Sparrows (Zonotrichia albicollis) during the last 4 days of the nestling period and the first 4 days of the fledgling period. Both parents made more provisioning trips and delivered more food to fledglings than to nestlings. Though male and female parents provided nestlings with equal amounts of food, female parents provided fledglings with more food than did male parents. Fledglings received fewer items per trip than did nestlings. This suggests that fledging was associated with a change in parental foraging strategies. Postfledging parental care did not differ between broods from late nests and broods that were to be followed by a second nesting attempt.
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An experimental study of brood division in White-Throated Sparrows
Animal Behaviour, 1991Co-Authors: Jeffrey G. Kopachena, J. Bruce FallsAbstract:Abstract Parental care towards experimentally restrained White-Throated Sparrow, Zonotrichia albicollis , fledglings was examined for evidence of brood division. Brood division occurred in 14 of 17 broods and was characterized by distinct but overlapping preferences by parents for particular brood members. The combined efforts of the parents usually resulted in an even distribution of resources among the brood. However, in some cases, brood division caused some fledglings to receive more food than others. Within-brood variation in food received was correlated with the difference between parents in parental effort. Brood division was maintained by the location of the young for some parents and by the identity of the young for other parents. It is suggested that changes in brood mobility might necessitate a shift in the cues used to discriminate between fledglings in order for parents to maintain brood division through the post-fledging period.
Rusty A. Gonser - One of the best experts on this subject based on the ideXlab platform.
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Quantitative color variation within and across morphs of the polymorphic White-Throated Sparrow
The Auk, 2020Co-Authors: Nathan A. Rathbun, Rusty A. Gonser, Andrea S. Grunst, Melissa L. Grunst, Joanna K. Hubbard, Rebecca J. Safran, Elaina M. TuttleAbstract:ABSTRACT Coloration has evolved to serve diverse functions, including communication. In species with discrete color polymorphisms, the extent to which color variation exists within morphs and communicates multiple messages often remains unclear. We employed reflectance spectrometry to study variation in coloration in the dimorphic White-Throated Sparrow (Zonotrichia albicollis), which exhibits a “white” and “tan” morph in both sexes. We explored whether distinct color traits distinguish between morph and sex classes, and whether color variation exists within classes that might reflect differences in individual quality. Further, we asked whether sexual dichromatism is more pronounced in the white morph, in which males display greater promiscuity and aggression and, thus, may be under stronger sexual selection for conspicuous coloration. Distinct aspects of crown plumage coloration differentiated the two morphs versus the two sexes and multiple types of coloration were associated with a morph, suggesting bo...
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Negative-Assortative Mating in the White-Throated Sparrow.
Journal of Heredity, 2017Co-Authors: Philip W. Hedrick, Elaina M. Tuttle, Rusty A. GonserAbstract:: Nonrandom mating based on phenotype has been observed in a number of organisms, but a very high proportion of these examples are of assortative mating. The strongest example of negative-assortative mating is for white-striped versus tan-striped crown in the White-Throated Sparrow, where about 98% of the observed pairings (mated pairs or social pairs) are between mates with different phenotypes and the correlation between mating types is -0.964. Although nonrandom mating has been explored theoretically for decades, these models have generally not focused on specific well-documented examples. Here we have developed a model to investigate the dynamics and equilibrium of this iconic example. The observed pattern of mating appears to be the result of 96% negative-assortative mating and a 17% advantage of W (white) male × T (tan) female matings compared to the reciprocal T male × W female matings. The equilibrium heterozygosity given these values is 0.500, very close to the 0.501 observed in our large sample of pairings, and this heterozygosity has been maintained for the 29 years from 1988 to 2016. In addition, the equilibrium frequency of 2m inversion determining the white-striped phenotype has been maintained at a frequency very close to its equilibrium frequency of 0.25. Overall, this model demonstrates how evolutionary genetic models can be used to understand negative-assortative mating.
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Genetic Verification of Dizygotic Twin Embryos in the White-Throated Sparrow (Zonotrichia albicollis)
The Wilson Journal of Ornithology, 2015Co-Authors: Adam M. Betuel, Elaina M. Tuttle, Rusty A. GonserAbstract:The incidence of twinning in avian species is a phenomenon that has been rarely encoun- tered. A number of domestic species have been shown to produce twins but in very low numbers. In wild populations, only 14 species have been documented producing twin embryos or nestlings. Despite this, it has been postulated that birds are just as likely as any other vertebrate to produce twin offspring. Here we describe the discovery of dizygotic twins in a long-term study of breeding ecology in the White-Throated Sparrow (Zonotrichia albicollis). The twin containing egg was 12% heavier than the mean and had a mass greater than 94% of eggs collected. The twin containing egg was wider and longer than the majority of other eggs collected during 2010 but still within the expected range for White-Throated Sparrows. Genetic analysis demon- strated that the twin embryos were full siblings but of different morph and sex. This is the first documented case of twinning in our study site out of over 2000 samples over 25 years of study, and likely the first confirmed case of twinning in this species. Received 30 June 2014. Accepted 27 March 2015.
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Variation in Preen Oil Composition Pertaining to Season, Sex, and Genotype in the Polymorphic White-Throated Sparrow
Journal of Chemical Ecology, 2014Co-Authors: Elaina M. Tuttle, Peter J. Sebastian, Amanda L. Posto, Helena A. Soini, Milos V. Novotny, Rusty A. GonserAbstract:Evidence for the the ability of birds to detect olfactory signals is now well documented, yet it remains unclear whether birds secrete chemicals that can be used as social cues. A potential source of chemical cues in birds is the secretion from the uropygial gland, or preen gland, which is thought to waterproof, maintain, and protect feathers from ectoparasites. However, it is possible that preen oil also may be used for individual recognition, mate choice, and signalling social/sexual status. If preen oil secretions can be used as socio-olfactory signals, we should be able to identify the volatile components that could make the secretions more detectable, determine the seasonality of these secretions, and determine whether olfactory signals differ among relevant social groups. We examined the seasonal differences in volatile compounds of the preen oil of captive White-Throated Sparrows, Zonotrichia albicollis. This species is polymorphic and has genetically determined morphs that occur in both sexes. Mating is almost exclusively disassortative with respect to morph, suggesting strong mate choice. By sampling the preen oil from captive birds in breeding and non-breeding conditions, we identified candidate chemical signals that varied according to season, sex, morph, and species. Linear alcohols with a 10–18 carbon chains, as well as methyl ketones and carboxylic acids, were the most abundant volatile compounds. Both the variety and abundances of some of these compounds were different between the sexes and morphs, with one morph secreting more volatile compounds in the non-breeding season than the other. In addition, 12 compounds were seasonally elevated in amount, and were secreted in high amounts in males. Finally, we found that preen oil signatures tended to be species-specific, with White-Throated Sparrows differing from the closely related Junco in the abundances and/or prevalence of at least three compounds. Our data suggest roles for preen oil secretions and avian olfaction in both non-social as well as social interactions.
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Whole genome sequence of the behaviorally polymorphic White-Throated Sparrow. 1: Mapping genes for sociogenomics
2014Co-Authors: Elaina M. Tuttle, Rusty A. Gonser, Michael N Romanov, Marisa L. Korody, Marlys L. Houck, Oliver A. Ryder, Teri L. Lear, Christopher N. Balakrishnan, Alan O. Bergland, Wesley C. WarrenAbstract:Chromosomal inversions are thought to lead to adaptation and speciation as they reduce recombination thereby protecting favorable genetic linkages. If this is the case, it is predicted that beneficial combinations of genes associated with fitness be located within chromosomal inversions. Here, we use whole genome sequencing and mapping with bacterial artificial chromosomes (BAC) to understand how gene arrangement leads to the morphological, behavioral, and physiological differences exhibited by two morphs of the White-Throated Sparrow (Zonotrichia albicollis). In this species, both sexes occur as white or tan morphs that have adopted alternative life-history strategies. Morph is determined by the presence or absence of a large rearrangement, which limits recombination of the second autosome. We have amassed 25 years of detailed data on this species making it possible to identify the genetic, epigenetic, and environmental bases of behavior. To begin these analyses we generated a high-quality 1Gb reference genome with N50 contig length of 104kb and scaffold length of 4.9Mb. We then used high-resolution BAC mapping to anchor the genome, and in doing so we were able to identify the breakpoint in this chromosome as well as several other smaller rearrangements of gene order. Despite considerable synteny in avian genomes, evolutionary analyses indicate minimums of 11 rearrangements between white and tan morphs, 35 rearrangements between chicken and Sparrow, and 26 rearrangements between zebra finch and Sparrow. Morphs of the White-Throated Sparrow provide a unique opportunity to study intraspecific genomic differences, which have resulted from two separate, yet linked evolutionary trajectories - such results can transform our understanding of the evolution of genomes as well as highlight the importance of inversions as drivers of evolution.
