Disease susceptibility in California sea lions

Short Communication Sequence variation and gene duplication at the MHC DRB loci of the spotted seal Phoca largha

“…The high level of spotted seal MHC-DRB polymorphism revealed in the present study has not been reported for the Phocidae and could be a consequence of the small spotted seal population adapting to the Bohai Sea, which probably has a relatively 2056 X.G. Gao et al ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (1): 2055-2062(2015 high level of pathogens. …”

“…Although several hypotheses have been put forward to explain the reduction of MHC diversity in marine mammals, the simplest explanation is that the low level of MHC diversity is caused by a reduced balancing selection pressure, which in turn is the result of the lower abundance of parasites in marine water as compared to terrestrial environments (Slade, 1992). One problem with this hypothesis is the finding from previous studies that many diseases and epizootics do occur in marine mammal populations (Van Bressem et al, 1998;Acevedo-Whitehouse et al, 2003). Compared to the MHC genes of many other marine mammals, which show low levels of genetic diversity (Slade, 1992;Murray et al, 1995), the spotted seal genome showed evidence of gene duplication and had unexpectedly high levels of allelic diversity and sequence variability.…”

Contribution of consanguinuity to polygenic and multifactorial diseases

“…Hill, personal communication), and on traits such as blood pressure and several common late-onset diseases, after controlling for socioeconomic factors 6,7 . Second, inbreeding effects associated with homozygosity at disease susceptibility loci could result in epistatic effects that jointly impair the capacity to adapt to environmental risks, including infectious diseases 5 . Third, there is now evidence that heterozygote advantage at loci such as the major histocompatibility complex, which may be maintained by balancing selection, could be reduced by consanguinity 8 .…”

Extensive genome-wide autozygosity in the population isolates of Daghestan

“…[1][2][3][4] An effect of consanguineous mating recognizable in most organisms is inbreeding depression, defined as the reduced survival and fertility of offspring of related individuals. 5 A plausible explanation for inbreeding depression is increased homozygosity for partially recessive deleterious mutations (partial dominance).…”