The Experts below are selected from a list of 157524 Experts worldwide ranked by ideXlab platform

Linda Vigilant - One of the best experts on this subject based on the ideXlab platform.

  • RESEARCH ARTICLE Effects of Habitat Fragmentation, Population Size and Demographic History on Genetic Diversity: The Cross River Gorilla in a Comparative Context
    2008
    Co-Authors: Richard A Bergl, Brenda J. Bradley, Anthony M. Nsubuga, Linda Vigilant
    Abstract:

    In small and fragmented populations, genetic diversity may be reduced owing to increased levels of drift and inbreeding. This reduced diversity is often associated with decreased fitness and a higher threat of extinction. However, it is difficult to determine when a population has low diversity except in a Comparative Context. We assessed genetic variability in the critically endangered Cross River gorilla (Gorilla gorilla diehli), a small and fragmented population, using 11 autosomal microsatellite loci. We show that levels of diversity in the Cross River population are not evenly distributed across the three genetically identified subpopulations, and that one centrally located subpopulation has higher levels of variability than the others. All measures of genetic variability in the Cross River population were comparable to those of the similarly small mountain gorilla (G. beringei beringei) populations (Bwindi and Virunga). However, for some measures both the Cross River and mountain gorilla populations show lower levels of diversity than a sample from a large, continuous western gorilla population (Mondika, G. gorilla gorilla). Finally, we tested for the genetic signature of a bottleneck in each of the four populations. Only Cross River showed strong evidence of a reduction in population size, suggesting that the reduction in size of this population was more recent or abrupt than in the two mountain gorilla populations. These results emphasize the need for maintaining connectivity in fragmented populations and highlight the importance of allowing small populations to expand. Am. J. Primatol. 70:848‐859, 2008. � c 2008 Wiley-Liss, Inc.

  • Effects of habitat fragmentation, population size and demographic history on genetic diversity: the cross river gorilla in a Comparative Context
    American journal of primatology, 2008
    Co-Authors: Richard A Bergl, Brenda J. Bradley, Anthony M. Nsubuga, Linda Vigilant
    Abstract:

    In small and fragmented populations, genetic diversity may be reduced owing to increased levels of drift and inbreeding. This reduced diversity is often associated with decreased fitness and a higher threat of extinction. However, it is difficult to determine when a population has low diversity except in a Comparative Context. We assessed genetic variability in the critically endangered Cross River gorilla (Gorilla gorilla diehli), a small and fragmented population, using 11 autosomal microsatellite loci. We show that levels of diversity in the Cross River population are not evenly distributed across the three genetically identified subpopulations, and that one centrally located subpopulation has higher levels of variability than the others. All measures of genetic variability in the Cross River population were comparable to those of the similarly small mountain gorilla (G. beringei beringei) populations (Bwindi and Virunga). However, for some measures both the Cross River and mountain gorilla populations show lower levels of diversity than a sample from a large, continuous western gorilla population (Mondika, G. gorilla gorilla). Finally, we tested for the genetic signature of a bottleneck in each of the four populations. Only Cross River showed strong evidence of a reduction in population size, suggesting that the reduction in size of this population was more recent or abrupt than in the two mountain gorilla populations. These results emphasize the need for maintaining connectivity in fragmented populations and highlight the importance of allowing small populations to expand. Am. J. Primatol. 70:848–859, 2008. © 2008 Wiley-Liss, Inc.

Jacqueline F. Webb - One of the best experts on this subject based on the ideXlab platform.

  • Considering the zebrafish in a Comparative Context.
    Journal of experimental zoology. Part B Molecular and developmental evolution, 2007
    Co-Authors: Thomas F. Schilling, Jacqueline F. Webb
    Abstract:

    This article introduces a special issue on zebrafish biology that attempts to integrate developmental genetics with Comparative studies of other fish species. For zebrafish researchers, Comparative work offers a better understanding of the evolutionary history of their model system. Comparative biologists can gain many insights from the developmental and genetic mechanisms revealed in zebrafish that have contributed to the huge range of morphological variation among fishes that has arisen over millions of years. These ideas are considered here in various Contexts, including systematics, genome organization and the development of the nervous system, pigmentation, craniofacial skeleton and dentition. Studies of the zebrafish in phylogenetic Context provide an opportunity for synergy between communities using these two fundamentally different approaches.

  • Zebrafish in Comparative Context: A symposium
    Integrative and comparative biology, 2006
    Co-Authors: Jacqueline F. Webb, Thomas F. Schilling
    Abstract:

    The Symposium "Zebrafish in Comparative Context" was organized to bring together two largely separate but highly complementary research traditions in order to make developmental and genetic information about a model species (Danio rerio, the zebrafish) more accessible to the Comparative biology community. The meeting focused on the relationship of this model organism to other vertebrates (particularly other fishes) using a Comparative and evolutionary approach. Topics included the phylogeny of cypriniform fishes, genome evolution, the evolution of gastrulation, dentition, pigmentation, craniofacial development, and nervous system structure and function. Participants also met informally to discuss ways to facilitate collaborative projects in areas of common interest and determine priorities for the development of shared resources. Continuing interactions between Comparative biologists, with their extensive body of knowledge of morphological variation among fish species, and developmental biologists and geneticists working with model species such as the zebrafish will facilitate our understanding of the evolution of developmental patterns and processes in vertebrates.

Thomas F. Schilling - One of the best experts on this subject based on the ideXlab platform.

  • Considering the zebrafish in a Comparative Context.
    Journal of experimental zoology. Part B Molecular and developmental evolution, 2007
    Co-Authors: Thomas F. Schilling, Jacqueline F. Webb
    Abstract:

    This article introduces a special issue on zebrafish biology that attempts to integrate developmental genetics with Comparative studies of other fish species. For zebrafish researchers, Comparative work offers a better understanding of the evolutionary history of their model system. Comparative biologists can gain many insights from the developmental and genetic mechanisms revealed in zebrafish that have contributed to the huge range of morphological variation among fishes that has arisen over millions of years. These ideas are considered here in various Contexts, including systematics, genome organization and the development of the nervous system, pigmentation, craniofacial skeleton and dentition. Studies of the zebrafish in phylogenetic Context provide an opportunity for synergy between communities using these two fundamentally different approaches.

  • Zebrafish in Comparative Context: A symposium
    Integrative and comparative biology, 2006
    Co-Authors: Jacqueline F. Webb, Thomas F. Schilling
    Abstract:

    The Symposium "Zebrafish in Comparative Context" was organized to bring together two largely separate but highly complementary research traditions in order to make developmental and genetic information about a model species (Danio rerio, the zebrafish) more accessible to the Comparative biology community. The meeting focused on the relationship of this model organism to other vertebrates (particularly other fishes) using a Comparative and evolutionary approach. Topics included the phylogeny of cypriniform fishes, genome evolution, the evolution of gastrulation, dentition, pigmentation, craniofacial development, and nervous system structure and function. Participants also met informally to discuss ways to facilitate collaborative projects in areas of common interest and determine priorities for the development of shared resources. Continuing interactions between Comparative biologists, with their extensive body of knowledge of morphological variation among fish species, and developmental biologists and geneticists working with model species such as the zebrafish will facilitate our understanding of the evolution of developmental patterns and processes in vertebrates.

Richard A Bergl - One of the best experts on this subject based on the ideXlab platform.

  • RESEARCH ARTICLE Effects of Habitat Fragmentation, Population Size and Demographic History on Genetic Diversity: The Cross River Gorilla in a Comparative Context
    2008
    Co-Authors: Richard A Bergl, Brenda J. Bradley, Anthony M. Nsubuga, Linda Vigilant
    Abstract:

    In small and fragmented populations, genetic diversity may be reduced owing to increased levels of drift and inbreeding. This reduced diversity is often associated with decreased fitness and a higher threat of extinction. However, it is difficult to determine when a population has low diversity except in a Comparative Context. We assessed genetic variability in the critically endangered Cross River gorilla (Gorilla gorilla diehli), a small and fragmented population, using 11 autosomal microsatellite loci. We show that levels of diversity in the Cross River population are not evenly distributed across the three genetically identified subpopulations, and that one centrally located subpopulation has higher levels of variability than the others. All measures of genetic variability in the Cross River population were comparable to those of the similarly small mountain gorilla (G. beringei beringei) populations (Bwindi and Virunga). However, for some measures both the Cross River and mountain gorilla populations show lower levels of diversity than a sample from a large, continuous western gorilla population (Mondika, G. gorilla gorilla). Finally, we tested for the genetic signature of a bottleneck in each of the four populations. Only Cross River showed strong evidence of a reduction in population size, suggesting that the reduction in size of this population was more recent or abrupt than in the two mountain gorilla populations. These results emphasize the need for maintaining connectivity in fragmented populations and highlight the importance of allowing small populations to expand. Am. J. Primatol. 70:848‐859, 2008. � c 2008 Wiley-Liss, Inc.

  • Effects of habitat fragmentation, population size and demographic history on genetic diversity: the cross river gorilla in a Comparative Context
    American journal of primatology, 2008
    Co-Authors: Richard A Bergl, Brenda J. Bradley, Anthony M. Nsubuga, Linda Vigilant
    Abstract:

    In small and fragmented populations, genetic diversity may be reduced owing to increased levels of drift and inbreeding. This reduced diversity is often associated with decreased fitness and a higher threat of extinction. However, it is difficult to determine when a population has low diversity except in a Comparative Context. We assessed genetic variability in the critically endangered Cross River gorilla (Gorilla gorilla diehli), a small and fragmented population, using 11 autosomal microsatellite loci. We show that levels of diversity in the Cross River population are not evenly distributed across the three genetically identified subpopulations, and that one centrally located subpopulation has higher levels of variability than the others. All measures of genetic variability in the Cross River population were comparable to those of the similarly small mountain gorilla (G. beringei beringei) populations (Bwindi and Virunga). However, for some measures both the Cross River and mountain gorilla populations show lower levels of diversity than a sample from a large, continuous western gorilla population (Mondika, G. gorilla gorilla). Finally, we tested for the genetic signature of a bottleneck in each of the four populations. Only Cross River showed strong evidence of a reduction in population size, suggesting that the reduction in size of this population was more recent or abrupt than in the two mountain gorilla populations. These results emphasize the need for maintaining connectivity in fragmented populations and highlight the importance of allowing small populations to expand. Am. J. Primatol. 70:848–859, 2008. © 2008 Wiley-Liss, Inc.

David R. Samson - One of the best experts on this subject based on the ideXlab platform.

  • Sleep in a Comparative Context: Investigating how human sleep differs from sleep in other primates.
    American journal of physical anthropology, 2018
    Co-Authors: Charles L. Nunn, David R. Samson
    Abstract:

    Objectives Primates vary in their sleep durations and, remarkably, humans sleep the least per 24-hr period of the 30 primates that have been studied. Using phylogenetic methods that quantitatively situate human phenotypes within a broader primate Comparative Context, we investigated the evolution of human sleep architecture, focusing on: total sleep duration, rapid eye movement (REM) sleep duration, non-rapid eye movement (NREM) sleep duration, and proportion of sleep in REM. Materials and Methods We used two different Bayesian methods: phylogenetic prediction based on phylogenetic generalized least squares and a multistate Onrstein-Uhlenbeck (OU) evolutionary model of random drift and stabilizing selection. Results Phylogenetic prediction confirmed that humans sleep less than predicted for a primate of our body mass, predation risk, brain size, foraging needs, sexual selection, and diet. These analyses further revealed that humans pack an unexpectedly higher proportion of REM sleep within a shorter overall sleep duration, and do so by reducing NREM sleep (rather than increasing REM). The OU model generally confirmed these findings, with shifts along the human lineage inferred for TST, NREM, and proportion of REM, but not for REM. Discussion We propose that the risks and opportunity costs of sleep are responsible for shorter sleep durations in humans, with risks arising from terrestrial sleep involving threats from predators and conspecifics, and opportunity costs because time spent sleeping could be used for learning, creating material objects, and socializing.