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Mats Olsson - One of the best experts on this subject based on the ideXlab platform.
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contrasting seasonal patterns of telomere dynamics in response to environmental conditions in the ectothermic sand lizard Lacerta Agilis
Scientific Reports, 2020Co-Authors: Jannike Axelsson, Erik Wapstra, Emily J Miller, Nicky Rollings, Mats OlssonAbstract:Telomeres, the protective, terminal parts of the chromosomes erode during cell division and as a result of oxidative damage by reactive oxygen species (ROS). Ectotherms rely on the ambient temperature for maintaining temperature-dependent metabolic rate, regulated through behavioural thermoregulation. Their temperature-dependant metabolism, hence also the ROS production, is indirectly regulated through thermoregulation. Consequently, a potential causal chain affecting telomere length and attrition is: temperature (in particular, its deviation from a species-specific optimum) - metabolism - ROS production - anti-oxidation - telomere erosion. We measured telomere length in sand lizards (Lacerta Agilis) using qPCR on blood samples from 1998-2006. Effects of climatological parameters (mean temperature and average sunshine hours) in the summer and winter preceding telomere sampling were used as predictors of telomere length in mixed model analysis. During the lizards' active period (summer), there was a largely negative effect of mean temperature and sun on telomere length, whereas a combined measure of age and size (head length) was positively related to telomere length. During the inactive period of lizards (winter), the results were largely the opposite with a positive relationship between temperature and sunshine hours and telomere length. In all four cases, thermal and age effects on telomere length appeared to be non-linear in the two sexes and seasons, with complex response surface effects on telomere length from combined age and thermal effects.
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Proximate determinants of telomere length in sand lizards ( References Subject collections Proximate determinants of telomere length in sand lizards (Lacerta Agilis)
2020Co-Authors: Biol Mats Lett, Mats Olsson, Angela Pauliny, Angela Olsson, Erik Pauliny, Donald Wapstra, ) Blomqvist, Erik Wapstra, Donald BlomqvistAbstract:Telomeres are repeat sequences of non-coding DNA that cap the ends of chromosomes and contribute to their stability and the genomic integrity of cells. In evolutionary ecology, the main research target regarding these genomic structures has been their role in ageing and as a potential index of age. However, research on humans shows that a number of traits contribute to among-individual differences in telomere length, in particular traits enhancing cell division and genetic erosion, such as levels of free radicals and stress. In lizards, tail loss owing to predation attempts results in a stress-induced shift to a more cryptic lifestyle. In sand lizard (Lacerta Agilis) males, telomere length was compromised by tail regrowth in a body size-related manner, so that small males, which already exhibit more cryptic mating tactics, were less affected than larger males. Tail regrowth just fell short of having a significant relationship with telomere length in females, and so did age in males. In females, there was a significant positive relationship between age and telomere length. We conclude that the proximate effect of compromised antipredation and its associated stress seems to have a more pronounced effect in males than in females and that age-associated telomere dynamics differ between the sexes
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Sand lizard (Lacerta Agilis) phenology in a warming world
2016Co-Authors: Gabriella Ljungstrom, Erik Wapstra, Mats OlssonAbstract: -
no interstitial telomeres on autosomes but remarkable amplification of telomeric repeats on the w sex chromosome in the sand lizard Lacerta Agilis
Journal of Heredity, 2015Co-Authors: Kazumi Matsubara, Kornsorn Srikulnath, Yoshinobu Uno, Yoichi Matsuda, Emily J Miller, Mats OlssonAbstract:Telomeres are repeat (TTAGGG) n sequences that form terminal ends of chromosomes and have several functions, such as protecting the coding DNA from erosion at mitosis. Due to chromosomal rearrangements through evolutionary history (e.g., inversions and fusions), telomeric sequences are also found between the centromere and the terminal ends (i.e., at interstitial telomeric sites, ITSs). ITS telomere sequences have been implicated in heritable disease caused by genomic instability of ITS polymorphic variants, both with respect to copy number and sequence. In the sand lizard (Lacerta Agilis), we have shown that telomere length is predictive of lifetime fitness in females but not males. To assess whether this sex specific fitness effect could be traced to ITSs differences, we mapped (TTAGGG) n sequences using fluorescence in situ hybridization in fibroblast cells cultured from 4 specimens of known sex. No ITSs could be found on autosomes in either sex. However, females have heterogametic sex chromosomes in sand lizards (ZW, 2n = 38) and the female W chromosome showed degeneration and remarkable (TTAGGG) n amplification, which was absent in the Z chromosomes. This work warrants further research on sex chromosome content, in particular of the degenerate W chromosome, and links to female fitness in sand lizards.
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sand lizard Lacerta Agilis phenology in a warming world
BMC Evolutionary Biology, 2015Co-Authors: Gabriella Ljungstrom, Mats Olsson, Erik WapstraAbstract:Present-day climate change has altered the phenology (the timing of periodic life cycle events) of many plant and animal populations worldwide. Some of these changes have been adaptive, leading to an increase in population fitness, whereas others have been associated with fitness decline. Representing short-term responses to an altered weather regime, hitherto observed changes are largely explained by phenotypic plasticity. However, to track climatically induced shifts in optimal phenotype as climate change proceeds, evolutionary capacity in key limiting climate- and fitness-related traits is likely to be crucial. In order to produce realistic predictions about the effects of climate change on species and populations, a main target for conservation biologists is thus to assess the potential of natural populations to respond by these two mechanisms. In this study we use a large 15-year dataset on an ectotherm model, the Swedish sand lizard (Lacerta Agilis), to investigate how higher spring temperature is likely to affect oviposition timing in a high latitude population, a trait strongly linked to offspring fitness and survival. With an interest in both the short- and potential long-term effect of rising temperatures, we applied a random regression model, which yields estimates of population-level plasticity and among-individual variation in the average, as well as the plastic, response to temperature. Population plasticity represents capacity for short-term adjustments whereas variation among individuals in a fitness-related trait indicates an opportunity for natural selection and hence for evolutionary adaptation. The analysis revealed both population-level plasticity and individual-level variation in average laying date. In contrast, we found no evidence for variation among females in their plastic responses to spring temperature, which could demonstrate a similarity in responses amongst females, but may also be due to a lack of statistical power to detect such an effect. Our findings indicate that climate warming may have positive fitness effects in this lizard population through an advancement of oviposition date. This prediction is consistent over shorter and potentially also longer time scales as the analysis revealed both population-level plasticity and individual-level variation in average laying date. However, the genetic basis for this variation would have to be examined in order to predict an evolutionary response.
Hakan Tegelstrom - One of the best experts on this subject based on the ideXlab platform.
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population size and genetic diversity in sand lizards Lacerta Agilis and adders vipera berus
Biological Conservation, 2000Co-Authors: Mats Olsson, Thomas Madsen, Bo Stille, Richard Shine, Hakan Wittzell, Annica Gullberg, Stefan Andersson, Hakan TegelstromAbstract:Because low genetic diversity may threaten the viability of isolated populations, conservation biologists have devoted much effort to quantify genetic variation. Two techniques routinely used involve levels of mini- and microsatellite polymorphism, with the assumption that levels of variation at these parts of the genome will be reflected in levels of variation at other loci. Our data challenge this assumption. We studied six populations of sand lizards (Lacerta Agilis) and five populations of adders (Vipera berus), differing considerably in size and degree of isolation. They, therefore, offer an opportunity to examine how population parameters affect genetic variation at different parts of the genome. Relative population size (based on degree of isolation and number of animals) was not correlated with either minisatellite variability or microsatellite heterozygosity. However, our measures of genetic diversity at the Mhc class I loci of both sand lizards and adders revealed a significant correlation between relative population size and Mhc polymorphism: non-isolated/larger populations exhibited higher genetic diversity than did isolated/small populations. Consequently, only the Mhc-based estimates of genetic diversity yielded results in agreement with population genetic theory. (C) 2000 Elsevier Science Ltd. All rights reserved.
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population size and genetic diversity in sand lizards Lacerta Agilis and adders vipera berus
Biological Conservation, 2000Co-Authors: Mats Olsson, Thomas Madsen, Bo Stille, Richard Shine, Hakan Wittzell, Annica Gullberg, Stefan Andersson, Hakan TegelstromAbstract:Because low genetic diversity may threaten the viability of isolated populations, conservation biologists have devoted much effort to quantify genetic variation. Two techniques routinely used involve levels of mini- and microsatellite polymorphism, with the assumption that levels of variation at these parts of the genome will be reflected in levels of variation at other loci. Our data challenge this assumption. We studied six populations of sand lizards (Lacerta Agilis) and five populations of adders (Vipera berus), differing considerably in size and degree of isolation. They, therefore, offer an opportunity to examine how population parameters affect genetic variation at different parts of the genome. Relative population size (based on degree of isolation and number of animals) was not correlated with either minisatellite variability or microsatellite heterozygosity. However, our measures of genetic diversity at the Mhc class I loci of both sand lizards and adders revealed a significant correlation between relative population size and Mhc polymorphism: non-isolated/larger populations exhibited higher genetic diversity than did isolated/small populations. Consequently, only the Mhc-based estimates of genetic diversity yielded results in agreement with population genetic theory. (C) 2000 Elsevier Science Ltd. All rights reserved.
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colonization genetic diversity and evolution in the swedish sand lizard Lacerta Agilis reptilia squamata
Biological Journal of The Linnean Society, 1998Co-Authors: Annica Gullberg, Mats Olsson, Hakan TegelstromAbstract:The Swedish sand lizard (Lacerta Agilis) is a relict species from the post-glacial warmth period. From the geological history of this region, and more recent data on population fragmentation due to disturbance by man, it can be surmised that the Swedish sand lizards passed through at least one population bottleneck in relatively recent times. We tested this hypothesis by investigating the amount and structuring of genetic variability in six microsatellite loci in ten lizard populations from different parts of Sweden. We contrasted these data against those from a Hungarian population which we have reason to assume strongly resembles the founder population for Swedish sand lizards. The average number of alleles per locus in Sweden was 3.3, and these alleles were common in almost all populations, whereas the average number of alleles in the Hungarian population was 8.0. Likewise, the level of expected heterozygosity was lower in the Swedish populations (0.45) compared to the Hungarian population (0.70). The lower variability in Swedish populations is probably a consequence of a common population bottleneck during the immigration subsequent to the latest glacial period. The remaining variability is strongly subdivided between populations (FST=0.30) with the main genetic differences being between rather than within populations. Despite the marked isolation of the populations and the present small population sizes (N= 10–300 adults), the Swedish relict populations show a surprisingly high level of observed heterozygosity, indicating that small population size is probably a recent phenomenon.
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regular articlecolonization genetic diversity and evolution in the swedish sand lizard Lacerta Agilis reptilia squamata
Biological Journal of The Linnean Society, 1998Co-Authors: Annica Gullberg, Mats Olsson, Hakan TegelstromAbstract:The Swedish sand lizard (Lacerta Agilis) is a relict species from the post-glacial warmth period. From the geological history of this region, and more recent data on population fragmentation due to disturbance by man, it can be surmised that the Swedish sand lizards passed through at least one population bottleneck in relatively recent times. We tested this hypothesis by investigating the amount and structuring of genetic variability in six microsatellite loci in ten lizard populations from different parts of Sweden. We contrasted these data against those from a Hungarian population which we have reason to assume strongly resembles the founder population for Swedish sand lizards. The average number of alleles per locus in Sweden was 3.3, and these alleles were common in almost all populations, whereas the average number of alleles in the Hungarian population was 8.0. Likewise, the level of expected heterozygosity was lower in the Swedish populations (0.45) compared to the Hungarian population (0.70). The lower variability in Swedish populations is probably a consequence of a common population bottleneck during the immigration subsequent to the latest glacial period. The remaining variability is strongly subdivided between populations (FST=0.30) with the main genetic differences being between rather than within populations. Despite the marked isolation of the populations and the present small population sizes (N=10–300 adults), the Swedish relict populations show a surprisingly high level of observed heterozygosity, indicating that small population size is probably a recent phenomenon.
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Microsatellites in the Sand Lizard (Lacerta Agilis): Description, Variation, Inheritance, and Applicability
Biochemical Genetics, 1997Co-Authors: Annica Gullberg, Hakan Tegelstrom, Mats OlssonAbstract:We developed microsatellite markers for the sand lizard ( Lacerta Agilis ) to enable investigations of the genetic variability within and among populations with a heterogeneous spatial distribution in Sweden. The populations, which could not be characterized by variation in allozymes or mitochondrial DNA, had a substantial level of variability in microsatellite loci. However, the variability in Swedish populations was limited compared to a large, outbred Hungarian population. In the sand lizard, the number of (GT/CA) _n repeats was approximately three times higher than that for (CT/GA) _n. The number of repeats and the frequency of microsatellites were within the range reported for other species. Three of nine microsatellite loci showed alleles that could not be amplified, which is in agreement with recent reports describing microsatellite “null alleles” as a common occurrence. We discuss the caution which this calls for when calculating paternity probabilities and when estimating between-population allelic differentiation. A potential problem with different mutation rates for alleles within the same locus is discussed.
Piotr Tryjanowski - One of the best experts on this subject based on the ideXlab platform.
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sand lizards Lacerta Agilis with higher digit ratios are more likely to autotomy
Journal of Anatomy, 2020Co-Authors: Mikolaj Kaczmarski, Klaudia Ziemblinska, Piotr TryjanowskiAbstract:Digit ratio is a morphological feature regarded as a biomarker of the balance of sex hormones during early development. The exposure of embryos to a set of sex hormones and the mutual relations between those hormones cause the emergence of individual morphological and/or behavioural characteristics as well as differences between sexes. We have thus hypothesised that differences in one of these morphological traits-digit ratio-may be a proxy representing a tendency towards tail autotomy. The aim of this study is to investigate the digit ratio (2D:3D, 2D:4D, 3D:4D) of the sand lizard, Lacerta Agilis, Lacertidae, a species characterised by well-developed sexual dimorphism, whereby females are larger than males. We also tested associations between patterns in digit ratio and caudal autotomy, a common defensive mechanism among lizards. To our knowledge, the relationship between a tendency towards autotomy and digit ratio pattern has never been researched. To date, studies on autotomy have mainly focused on the consequences, costs or evolutionary background of tail loss. Hence, researchers examined mostly the frequency of autotomy in the context of predatory pressure or habitat conditions, omitting an individual's behavioural tendency to shed its tail. However, behavioural traits can affect an individual's exposure to predator attack and consequently the need to use an anti-predator strategy. Thus, following this logic, dropping the tail may be the result of the lizard's intraspecific personality characteristics, resulting from the effect of hormones on behaviour or innate traits. Therefore, we suggest that the inclusion of autotomy as a factor explaining observed digit ratio patterns and their variability between taxa has great potential. We used computerised measurements of photographed limbs to determine the length of digits. We found that the digit ratios for all four limbs were significantly lower in females than in males, excluding the 3D:4D ratio for the right hindlimbs. Therefore, the results confirmed the pattern already observed for most lizards. The novel element in our study is the detection of the relationship between a tendency towards caudal autotomy and digit ratio. Individuals with a tendency towards autotomy have a higher 2D:4D ratio in the right forelimbs and a lower 2D:3D ratio in the right hindlimbs. Obtained results suggest that these morphological characteristics are most likely related to intraspecific differences (between bold and shy individuals) which consequently may determine an individual's reaction or susceptibility to be a prey and escape behaviour. Thus, our results are probably the first attempt to link digit ratio to the susceptibility of lizards to tail autotomy.
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Locomotor performance of sand lizards (Lacerta Agilis): effects of predatory pressure and parasite load
acta ethologica, 2013Co-Authors: Anna Ekner-grzyb, Zofia Sajkowska, Krzysztof Dudek, Monika Gawałek, Piotr Skórka, Piotr TryjanowskiAbstract:Locomotor performance affects foraging efficiency, predator avoidance and consequently fitness. Agility and speed determine the animal's social status and reflect its condition. In this study, we test how predatory pressure and parasite load influences locomotor performance of wild specimens of the sand lizard Lacerta Agilis . Animals were chased on a 2-metre racetrack. Lizards with autotomy ran significantly faster than lizards with an intact tail, but there was no significant difference in running speed between individuals with fresh caudal autotomy and regenerated tails. Parasite presence and load, age and sex had no significant effect on speed. Our results indicate that autotomy either alters locomotory behaviour or that individuals with autotomised tails were those that previously survived contact with predators, and therefore represented a subgroup of the fastest individuals. Therefore, in general, predatory pressure but not parasites affected locomotor performance in lizards.
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Anaplasmataceae and Borrelia burgdorferi sensu lato in the sand lizard Lacerta Agilis and co-infection of these bacteria in hosted Ixodes ricinus ticks
Parasites & vectors, 2011Co-Authors: Anna Ekner, Viktória Majláthová, Igor Majláth, Zofia Sajkowska, Krzysztof Dudek, Piotr TryjanowskiAbstract:Background: Anaplasmataceae and Borrelia burgdorferi s.l. are important tick-borne bacteria maintained in nature by transmission between ticks and vertebrate hosts. However, the potential role of lizards as hosts has not been sufficiently studied. Results: The current study showed that 23 of 171 examined sand lizards Lacerta Agilis were PCR positive for Anaplasmataceae. The nucleotide sequences of the several selected PCR products showed 100% homology with Anaplasma spp. found in Ixodes ricinus collected in Tunisia and Morocco (AY672415 - AY672420). 1.2% of lizard collar scale samples were PCR positive for B. lusitaniae. In addition, 12 of 290 examined I. ricinus were PCR positive for B. burgdorferi s.l. and 82 were PCR positive for Anaplasmatacea. The number of ticks per lizard and the number of ticks PCR positive for both microorganisms per lizard were strongly correlated. Moreover, we found a significant correlation between numbers of ticks infected with Anaplasmataceae and with B. burgdorferi s.l. living on the same lizard. However, there was no significant correlation between detection of both bacteria in the same tick.
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anaplasmataceae and borrelia burgdorferi sensu lato in the sand lizard Lacerta Agilis and co infection of these bacteria in hosted ixodes ricinus ticks
Parasites & Vectors, 2011Co-Authors: Anna Ekner, Viktória Majláthová, Igor Majláth, Zofia Sajkowska, Krzysztof Dudek, Piotr TryjanowskiAbstract:Anaplasmataceae and Borrelia burgdorferi s.l. are important tick-borne bacteria maintained in nature by transmission between ticks and vertebrate hosts. However, the potential role of lizards as hosts has not been sufficiently studied. The current study showed that 23 of 171 examined sand lizards Lacerta Agilis were PCR positive for Anaplasmataceae. The nucleotide sequences of the several selected PCR products showed 100% homology with Anaplasma spp. found in Ixodes ricinus collected in Tunisia and Morocco (AY672415 - AY672420). 1.2% of lizard collar scale samples were PCR positive for B. lusitaniae. In addition, 12 of 290 examined I. ricinus were PCR positive for B. burgdorferi s.l. and 82 were PCR positive for Anaplasmatacea. The number of ticks per lizard and the number of ticks PCR positive for both microorganisms per lizard were strongly correlated. Moreover, we found a significant correlation between numbers of ticks infected with Anaplasmataceae and with B. burgdorferi s.l. living on the same lizard. However, there was no significant correlation between detection of both bacteria in the same tick. To the best of our knowledge, this is the first report of Anaplasmataceae DNA and additionally the second report of B. burgdorferi s.l DNA detection in the sand lizard.
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Blood parasites in two co-existing species of lizards (Zootoca vivipara and Lacerta Agilis)
Parasitology Research, 2010Co-Authors: Viktória Majláthová, Igor Majláth, Božena Haklová, Martin Hromada, Anna Ekner, Marcin Antczak, Piotr TryjanowskiAbstract:We investigated the occurrence of blood parasites of two lizard species: the common or viviparous lizard ( Zootoca vivipara ) and the sand lizard ( Lacerta Agilis ) in western Poland. Selected traits of lizard body morphology were studied with respect to the presence and intensity of haematozoan infection in blood samples collected from 218 adult lizards; 88 of the common lizard and 130 of the sand lizard. Haemogregarinid blood parasites were found to be the common parasite of both lizard species in studied locality with prevalence 39.8 (95% CL, 29.5–50.8) for Z. vivipara and 22.3 (95% CL, 15.5–30.4) for L. Agilis . Incidence of parasitemia did not differ between sexes and was not correlated with morphological traits or presence of ectoparasites— Ixodes ricinus ticks. However, a significant difference between the two species of lizards was a greater frequency of haemogregarinid parasitism in Z. vivipara .
Annica Gullberg - One of the best experts on this subject based on the ideXlab platform.
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population size and genetic diversity in sand lizards Lacerta Agilis and adders vipera berus
Biological Conservation, 2000Co-Authors: Mats Olsson, Thomas Madsen, Bo Stille, Richard Shine, Hakan Wittzell, Annica Gullberg, Stefan Andersson, Hakan TegelstromAbstract:Because low genetic diversity may threaten the viability of isolated populations, conservation biologists have devoted much effort to quantify genetic variation. Two techniques routinely used involve levels of mini- and microsatellite polymorphism, with the assumption that levels of variation at these parts of the genome will be reflected in levels of variation at other loci. Our data challenge this assumption. We studied six populations of sand lizards (Lacerta Agilis) and five populations of adders (Vipera berus), differing considerably in size and degree of isolation. They, therefore, offer an opportunity to examine how population parameters affect genetic variation at different parts of the genome. Relative population size (based on degree of isolation and number of animals) was not correlated with either minisatellite variability or microsatellite heterozygosity. However, our measures of genetic diversity at the Mhc class I loci of both sand lizards and adders revealed a significant correlation between relative population size and Mhc polymorphism: non-isolated/larger populations exhibited higher genetic diversity than did isolated/small populations. Consequently, only the Mhc-based estimates of genetic diversity yielded results in agreement with population genetic theory. (C) 2000 Elsevier Science Ltd. All rights reserved.
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population size and genetic diversity in sand lizards Lacerta Agilis and adders vipera berus
Biological Conservation, 2000Co-Authors: Mats Olsson, Thomas Madsen, Bo Stille, Richard Shine, Hakan Wittzell, Annica Gullberg, Stefan Andersson, Hakan TegelstromAbstract:Because low genetic diversity may threaten the viability of isolated populations, conservation biologists have devoted much effort to quantify genetic variation. Two techniques routinely used involve levels of mini- and microsatellite polymorphism, with the assumption that levels of variation at these parts of the genome will be reflected in levels of variation at other loci. Our data challenge this assumption. We studied six populations of sand lizards (Lacerta Agilis) and five populations of adders (Vipera berus), differing considerably in size and degree of isolation. They, therefore, offer an opportunity to examine how population parameters affect genetic variation at different parts of the genome. Relative population size (based on degree of isolation and number of animals) was not correlated with either minisatellite variability or microsatellite heterozygosity. However, our measures of genetic diversity at the Mhc class I loci of both sand lizards and adders revealed a significant correlation between relative population size and Mhc polymorphism: non-isolated/larger populations exhibited higher genetic diversity than did isolated/small populations. Consequently, only the Mhc-based estimates of genetic diversity yielded results in agreement with population genetic theory. (C) 2000 Elsevier Science Ltd. All rights reserved.
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colonization genetic diversity and evolution in the swedish sand lizard Lacerta Agilis reptilia squamata
Biological Journal of The Linnean Society, 1998Co-Authors: Annica Gullberg, Mats Olsson, Hakan TegelstromAbstract:The Swedish sand lizard (Lacerta Agilis) is a relict species from the post-glacial warmth period. From the geological history of this region, and more recent data on population fragmentation due to disturbance by man, it can be surmised that the Swedish sand lizards passed through at least one population bottleneck in relatively recent times. We tested this hypothesis by investigating the amount and structuring of genetic variability in six microsatellite loci in ten lizard populations from different parts of Sweden. We contrasted these data against those from a Hungarian population which we have reason to assume strongly resembles the founder population for Swedish sand lizards. The average number of alleles per locus in Sweden was 3.3, and these alleles were common in almost all populations, whereas the average number of alleles in the Hungarian population was 8.0. Likewise, the level of expected heterozygosity was lower in the Swedish populations (0.45) compared to the Hungarian population (0.70). The lower variability in Swedish populations is probably a consequence of a common population bottleneck during the immigration subsequent to the latest glacial period. The remaining variability is strongly subdivided between populations (FST=0.30) with the main genetic differences being between rather than within populations. Despite the marked isolation of the populations and the present small population sizes (N= 10–300 adults), the Swedish relict populations show a surprisingly high level of observed heterozygosity, indicating that small population size is probably a recent phenomenon.
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regular articlecolonization genetic diversity and evolution in the swedish sand lizard Lacerta Agilis reptilia squamata
Biological Journal of The Linnean Society, 1998Co-Authors: Annica Gullberg, Mats Olsson, Hakan TegelstromAbstract:The Swedish sand lizard (Lacerta Agilis) is a relict species from the post-glacial warmth period. From the geological history of this region, and more recent data on population fragmentation due to disturbance by man, it can be surmised that the Swedish sand lizards passed through at least one population bottleneck in relatively recent times. We tested this hypothesis by investigating the amount and structuring of genetic variability in six microsatellite loci in ten lizard populations from different parts of Sweden. We contrasted these data against those from a Hungarian population which we have reason to assume strongly resembles the founder population for Swedish sand lizards. The average number of alleles per locus in Sweden was 3.3, and these alleles were common in almost all populations, whereas the average number of alleles in the Hungarian population was 8.0. Likewise, the level of expected heterozygosity was lower in the Swedish populations (0.45) compared to the Hungarian population (0.70). The lower variability in Swedish populations is probably a consequence of a common population bottleneck during the immigration subsequent to the latest glacial period. The remaining variability is strongly subdivided between populations (FST=0.30) with the main genetic differences being between rather than within populations. Despite the marked isolation of the populations and the present small population sizes (N=10–300 adults), the Swedish relict populations show a surprisingly high level of observed heterozygosity, indicating that small population size is probably a recent phenomenon.
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Microsatellites in the Sand Lizard (Lacerta Agilis): Description, Variation, Inheritance, and Applicability
Biochemical Genetics, 1997Co-Authors: Annica Gullberg, Hakan Tegelstrom, Mats OlssonAbstract:We developed microsatellite markers for the sand lizard ( Lacerta Agilis ) to enable investigations of the genetic variability within and among populations with a heterogeneous spatial distribution in Sweden. The populations, which could not be characterized by variation in allozymes or mitochondrial DNA, had a substantial level of variability in microsatellite loci. However, the variability in Swedish populations was limited compared to a large, outbred Hungarian population. In the sand lizard, the number of (GT/CA) _n repeats was approximately three times higher than that for (CT/GA) _n. The number of repeats and the frequency of microsatellites were within the range reported for other species. Three of nine microsatellite loci showed alleles that could not be amplified, which is in agreement with recent reports describing microsatellite “null alleles” as a common occurrence. We discuss the caution which this calls for when calculating paternity probabilities and when estimating between-population allelic differentiation. A potential problem with different mutation rates for alleles within the same locus is discussed.
Thomas Madsen - One of the best experts on this subject based on the ideXlab platform.
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between year variation in determinants of offspring survival in the sand lizard Lacerta Agilis
Functional Ecology, 2001Co-Authors: Mats Olsson, Thomas MadsenAbstract:Summary 1. Life-history theory predicts that clutch size and offspring size should evolve to an optimal offspring size vs number (OSN) equilibrium. 2. Offspring size in Swedish Sand Lizards ( Lacerta Agilis ) decreases up to 60% during a female’s life with a concomitant increase in clutch size; why do female Sand Lizards not produce an offspring of approximately equal size through life, while adjusting clutch size in accordance with available resources? 3. Our results show that there is year-to-year variation in what factors determine female reproductive success, estimated by the number or proportion of recruits into the second year cohort. 4. In a year with relatively poor female growth rate, poor female condition and probably relatively low potential for resource acquisition, females mating with many partners did relatively better than females mating with fewer partners. 5. In the poor year, relatively larger offspring survived better than smaller ones. 6. In a year with relatively high resource levels, females producing both relatively large young and large clutches were favoured by selection. 7. Depending on environmental conditions, female ‘optimal tactics’ may differ between episodes of selection.
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promiscuity in sand lizards Lacerta Agilis and adder snakes vipera berus causes and consequences
Journal of Heredity, 2001Co-Authors: Mats Olsson, Thomas MadsenAbstract:We review postcopulatory phenomena in the Swedish sand lizard (Lacerta Agilis) and adder (Vipera berus), and in particular, links between female promiscuity, determinants of paternity, and offspring viability. In both species, females mate multiply and exhibit a positive relationship between the number of partners and offspring viability. We conclude that this relationship is most likely the result of variable genetic compatibility between mates arising from postcopulatory phenomena, predominantly assortative fertilization with respect to parental genotypes, However, males who were more successful at mate acquisition were also more successful in situations of sperm competition, suggesting a possible link between male (diploid and haploid) genetic quality per se and probability of fertilization, Neither the number of partners nor the number of matings influenced the risk of infertility in sand lizards, suggesting that selection for reduced risk of infertility is not a sufficient explanation for maintaining female promiscuity in this population. Finally, we conclude that the relatively low genetic variability exhibited by our study populations may have facilitated detection of genetic benefits compared to more outbred ones. However, recent work derived from outbred populations in other tars suggest a greater generality of the principles we discuss than previously may have been appreciated.
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population size and genetic diversity in sand lizards Lacerta Agilis and adders vipera berus
Biological Conservation, 2000Co-Authors: Mats Olsson, Thomas Madsen, Bo Stille, Richard Shine, Hakan Wittzell, Annica Gullberg, Stefan Andersson, Hakan TegelstromAbstract:Because low genetic diversity may threaten the viability of isolated populations, conservation biologists have devoted much effort to quantify genetic variation. Two techniques routinely used involve levels of mini- and microsatellite polymorphism, with the assumption that levels of variation at these parts of the genome will be reflected in levels of variation at other loci. Our data challenge this assumption. We studied six populations of sand lizards (Lacerta Agilis) and five populations of adders (Vipera berus), differing considerably in size and degree of isolation. They, therefore, offer an opportunity to examine how population parameters affect genetic variation at different parts of the genome. Relative population size (based on degree of isolation and number of animals) was not correlated with either minisatellite variability or microsatellite heterozygosity. However, our measures of genetic diversity at the Mhc class I loci of both sand lizards and adders revealed a significant correlation between relative population size and Mhc polymorphism: non-isolated/larger populations exhibited higher genetic diversity than did isolated/small populations. Consequently, only the Mhc-based estimates of genetic diversity yielded results in agreement with population genetic theory. (C) 2000 Elsevier Science Ltd. All rights reserved.
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population size and genetic diversity in sand lizards Lacerta Agilis and adders vipera berus
Biological Conservation, 2000Co-Authors: Mats Olsson, Thomas Madsen, Bo Stille, Richard Shine, Hakan Wittzell, Annica Gullberg, Stefan Andersson, Hakan TegelstromAbstract:Because low genetic diversity may threaten the viability of isolated populations, conservation biologists have devoted much effort to quantify genetic variation. Two techniques routinely used involve levels of mini- and microsatellite polymorphism, with the assumption that levels of variation at these parts of the genome will be reflected in levels of variation at other loci. Our data challenge this assumption. We studied six populations of sand lizards (Lacerta Agilis) and five populations of adders (Vipera berus), differing considerably in size and degree of isolation. They, therefore, offer an opportunity to examine how population parameters affect genetic variation at different parts of the genome. Relative population size (based on degree of isolation and number of animals) was not correlated with either minisatellite variability or microsatellite heterozygosity. However, our measures of genetic diversity at the Mhc class I loci of both sand lizards and adders revealed a significant correlation between relative population size and Mhc polymorphism: non-isolated/larger populations exhibited higher genetic diversity than did isolated/small populations. Consequently, only the Mhc-based estimates of genetic diversity yielded results in agreement with population genetic theory. (C) 2000 Elsevier Science Ltd. All rights reserved.
