Leslie A Knapp

Publications (62) View all

• Source

  Available from: uni-bielefeld.de

  Article: Geographic variation of the major histocompatibility complex in Eastern Atlantic grey seals (Halichoerus grypus).

  K Cammen, J I Hoffman, L A Knapp, J Harwood, W Amos
  [show abstract] [hide abstract]
  ABSTRACT: Pathogen-driven balancing selection maintains high genetic diversity in many vertebrates, particularly in the major histocompatibility complex (MHC) immune system gene family, which is often associated with disease susceptibility. In large natural populations where subpopulations face different pathogen pressures, the MHC should show greater genetic differentiation within a species than neutral markers. We examined genetic diversity at the MHC-DQB locus and nine putatively neutral microsatellite markers in grey seals (Halichoerus grypus) from eight United Kingdom (UK) colonies, the Faeroe Islands and Sable Island, Canada. Five DQB alleles were identified in grey seals, which varied in prevalence across the grey seal range. Among the seal colonies, significant differences in DQB allele and haplotype frequencies and in average DQB heterozygosity were observed. Additionally, the DQB gene exhibited greater differentiation among colonies compared with neutral markers, yet a weaker pattern of isolation by distance (IBD). After correcting for the underlying IBD pattern, subpopulations breeding in similar habitats were more similar to one another in DQB allele frequencies than populations breeding in different habitats, but the same did not hold true for microsatellites, suggesting that habitat-specific pathogen pressure influences MHC evolution. Overall, the data are consistent with selection at MHC-DQB loci in grey seals with both varying selective pressures and geographic population structure appearing to influence the DQB genetic composition of breeding colonies.
  Molecular Ecology 02/2011; 20(4):740-52. · 5.52 Impact Factor
• Source

  Available from: cnrs.fr

  Article: Opposites attract: MHC-associated mate choice in a polygynous primate.

  J M Setchell, M J E Charpentier, K M Abbott, E J Wickings, L A Knapp
  [show abstract] [hide abstract]
  ABSTRACT: We investigated reproduction in a semi-free-ranging population of a polygynous primate, the mandrill, in relation to genetic relatedness and male genetic characteristics, using neutral microsatellite and major histocompatibility complex (MHC) genotyping. We compared genetic dissimilarity to the mother and genetic characteristics of the sire with all other potential sires present at the conception of each offspring (193 offspring for microsatellite genetics, 180 for MHC). The probability that a given male sired increased as pedigree relatedness with the mother decreased, and overall genetic dissimilarity and MHC dissimilarity with the mother increased. Reproductive success also increased with male microsatellite heterozygosity and MHC diversity. These effects were apparent despite the strong influence of dominance rank on male reproductive success. The closed nature of our study population is comparable to human populations for which MHC-associated mate choice has been reported, suggesting that such mate choice may be especially important in relatively isolated populations with little migration to introduce genetic variation.
  Journal of Evolutionary Biology 10/2009; 23(1):136-48. · 3.28 Impact Factor
• Article: Studying shape in sexual signals: the case of primate sexual swellings.

  Huchard, J. Benavides, J. Setchell, M. Charpentier, A. Alvergne, L.A. Knapp, G. Cowlishaw, M. Raymond
  Behavioral Ecology and Sociobiology 01/2009; 63(8):1231-1242. · 3.18 Impact Factor
• Source

  Available from: pnas.org

  Article: Genetic diversity and reproductive success in mandrills (Mandrillus sphinx).

  M Charpentier, J M Setchell, F Prugnolle, L A Knapp, E J Wickings, P Peignot, M Hossaert-McKey
  [show abstract] [hide abstract]
  ABSTRACT: Recent studies of wild animal populations have shown that estimators of neutral genetic diversity, such as mean heterozygosity, are often correlated with various fitness traits, such as survival, disease susceptibility, or reproductive success. We used two estimators of genetic diversity to explore the relationship between heterozygosity and reproductive success in male and female mandrills (Mandrillus sphinx) living in a semifree ranging setting in Gabon. Because social rank is known to influence reproductive success in both sexes, we also examined the correlation between genetic diversity and social rank in females, and acquisition of alpha status in males, as well as length of alpha male tenure. We found that heterozygous individuals showed greater reproductive success, with both females and males producing more offspring. However, heterozygosity influenced reproductive success only in dominant males, not in subordinates. Neither the acquisition of alpha status in males, nor social rank in females, was significantly correlated with heterozygosity, although more heterozygous alpha males showed longer tenure than homozygous ones. We also tested whether the benefits of greater genetic diversity were due mainly to a genome-wide effect of inbreeding depression or to heterosis at one or a few loci. Multilocus effects best explained the correlation between heterozygosity and reproductive success and tenure, indicating the occurrence of inbreeding depression in this mandrill colony.
  Proceedings of the National Academy of Sciences 12/2005; 102(46):16723-8. · 9.68 Impact Factor
• Article: Denaturing gradient gel electrophoresis and its use in the detection of major histocompatibility complex polymorphism.

  L A Knapp
  [show abstract] [hide abstract]
  ABSTRACT: The major histocompatibility complex (MHC) has been studied extensively in humans and in mice and many methods are available for MHC typing of these well-characterized species. Studies of MHC variation in other species are ever increasing and researchers can choose one of a number of approaches for MHC typing of their species of interest. DNA sequencing is regarded as the 'gold standard' and it is frequently used for MHC typing. However, DNA sequencing is impractical when many individuals must be typed. Denaturing gradient gel electrophoresis (DGGE) offers a flexible and sensitive method for identifying and characterizing MHC alleles in any vertebrate species. This article reviews the theory and the practice of DGGE and examines the use of DGGE for MHC identification in various species. DGGE is compared to other similar techniques for MHC typing, such as single-stranded conformational polymorphism and reference strand-mediated conformational analysis. The advantages, problems, pitfalls and limitations of DGGE are considered and future perspectives on the use of DGGE for MHC typing are discussed.
  Tissue Antigens 04/2005; 65(3):211-9. · 2.59 Impact Factor