Divergent Patterns of Variation in Major Histocompatibility Complex Class Ii Alleles Among Antarctic Phocid Pinnipeds

Lehman, Niles; Decker, Debra J.; Stewart, Brent S.

doi:10.1644/bdw-010.1

Cited by 22 publications

(18 citation statements)

References 42 publications

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“…2), suggests, however, that other mechanisms are also shaping MHC variability in ungulates, although Rangifer is known to generally exhibit more genetic variability than other cervids (Cô té et al 2002). In other mammalian species such as pinnipeds, high levels of MHC variability have also been reported at extreme latitudes (Hoelzel et al 1999;Lehman et al 2004), suggesting once again that parasite-based balancing selection and population bottlenecks are not the sole factors influencing MHC polymorphism.…”

Section: Discussionmentioning

confidence: 99%

“…In marine mammals, a decreased exposure to pathogens and parasites due to the environment in which they occur has also been suggested as a potential cause of the low MHC variation reported in these species when compared to terrestrial mammals (Trowsdale et al 1989;Slade 1992;Murray et al 1995;but see Hoelzel et al 1999;Lehman et al 2004). Similarly, in terrestrial mammals Van Den Bussche et al (1999 proposed that Arctic ungulate species may be exposed to fewer pathogens and parasites than those living close to the equator and thus, MHC diversity would be lower in northern ungulates compared to those at lower latitudes.…”

Section: Introductionmentioning

confidence: 99%

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Low MHC DRB class II diversity in the mountain goat: past bottlenecks and possible role of pathogens and parasites

et al. 2006

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Major histocompatibility complex (MHC) genes are the most polymorphic in vertebrates and code for molecules playing a central role in pathogen resistance. We studied levels of MHC DRB class II diversity in a long-term study population of mountain goats (Oreamnos americanus) at Caw Ridge, Alberta, and two other populations from British Columbia, Canada. Only two alleles were found among the three populations sampled. The Caw Ridge population was fixed for one of the two MHC DRB alleles, but this lack of variation did not appear to have affected it negatively because the population doubled over two decades and had no history of any apparent infectious diseases. Past population bottlenecks during Pleistocene glaciations are thought to have been the main factor contributing to the low levels of MHC diversity in mountain goats, a hypothesis supported by our previous work reporting low polymorphism at neutral loci. Additionally, the limited MHC variability in mountain goats may be related to its northern distribution as we found that allelic diversity at MHC DRB class II in wild ungulates decreases with increasing latitude, possibly as a result of low parasite diversity at high latitudes. The low MHC variation in mountain goats and other northern ungulates such as muskoxen (Ovibos moschatus) may expose these species to population outbreaks that could be generated by introduced pathogens or northward shifts in the distribution of pathogens with global climate warming.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Low MHC DRB class II diversity in the mountain goat: past bottlenecks and possible role of pathogens and parasites

et al. 2006

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“…Moreover, infectious diseases may have important influences on genetic structure and evolution of some species, particularly those with small populations (cf. Weber et al, 2000;Lehman et al, 2004).…”

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confidence: 99%

Survey for Selected Pathogens and Evaluation of Disease Risk Factors for Endangered Hawaiian Monk Seals in the Main Hawaiian Islands

et al. 2006

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A recently reestablished and increasing population of Hawaiian monk seals in the main Hawaiian Islands (MHI) is encouraging for this endangered species. However, seals in the MHI may be exposed to a broad range of human, pet, livestock, and feral animal pathogens. Our objective was to determine the movement and foraging habitats of Hawaiian monk seals in the MHI relative to the potential exposure of seals to infectious diseases in near-shore marine habitats. We captured 18 monk seals in the MHI between January 27, 2004 and November 29, 2005, tested them for various infectious diseases, and then monitored the foraging movements of 11 of them using satellite-linked radio transmitters for the next 32-167 days. All seals tested negative for canine adenovirus, calicivirus, four morbilliviruses, phocine herpes virus, Leptospira sp., and feline and canine heartworm antigen/antibody. Six of the seals tested positive on complement fixation for Chlamydophila abortus (formerly Chlamydia psittaci). Four seals demonstrated positive titers to Sarcocystis neurona, two to Neospora caninum, and two to Toxoplasma gondii. Fecal cultures showed approximately half (n = 6) positive for E. coli 0157, no Salmonella sp., and only one with Campylobacter sp. Satellite monitored seals spent considerable time foraging, traveling, and resting in neritic waters close to human population centers, agricultural activity, and livestock ranges, and sources of land-based water runoff and sewage dispersal.Consequently, Hawaiian monk seals in the MHI may be at risk of exposure to several infectious disease agents associated with terrestrial animals that can contaminate marine habitats from runoff along drainages and that are known to cause disease in marine mammals. Further, some seals overlapped substantially in their use of coastal habitats and several moved among islands while foraging and were seen on beaches near each other.This suggests that diseased seals could infect healthy conspecifics throughout the MHI.

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“…As reported by previous studies that used the primers DQA1 and DQA2, our cloned products each contained one of two very divergent sets of sequences that could not be aligned with each other (Decker et al 2002 Lehman et al 2004). Comparison with sequences on NCBI GenBank revealed that the first set of sequences (519 clones, 55%) aligned closely to MHC sequences from the class II locus DOA, rather than DQA.…”

Section: Genetic Methods To Characterize Dqa Variation Across Individmentioning

confidence: 68%

“…This allele, LoafDQA*01, occurred in over half of our samples and may be common in multiple populations. Such high frequencies of a single DQA allele have previously been reported only in species with low polymorphism; for instance, only species with two or fewer alleles have produced frequencies for a single DQA allele that are greater than 0.5 (Antunes et al 1998;Lehman et al 2004;Weber et al 2004). One speculation is that LoafDQA*01 is common because it confers a selective advantage to individuals in resisting a disease that was or is highly prevalent.…”

Section: Discussionmentioning

confidence: 91%

Major histocompatibility complex variation and evolution at a single, expressed DQA locus in two genera of elephants

et al. 2010

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Genes of the vertebrate major histocompatibility complex (MHC) are crucial to defense against infectious disease, provide an important measure of functional genetic diversity, and have been implicated in mate choice and kin recognition. As a result, MHC loci have been characterized for a number of vertebrate species, especially mammals; however, elephants are a notable exception. Our study is the first to characterize patterns of genetic diversity and natural selection in the elephant MHC. We did so using DNA sequences from a single, expressed DQA locus in elephants. We characterized six alleles in 30 African elephants (Loxodonta africana) and four alleles in three Asian elephants (Elephas maximus). In addition, for two of the African alleles and three of the Asian alleles, we characterized complete coding sequences (exons 1-5) and nearly complete non-coding sequences (introns 2-4) for the class II DQA loci. Compared to DQA in other wild mammals, we found moderate polymorphism and allelic diversity and similar patterns of selection; patterns of non-synonymous and synonymous substitutions were consistent with balancing selection acting on the peptides involved in antigen binding in the second exon. In addition, balancing selection has led to strong trans-species allelism that has maintained multiple allelic lineages across both genera of extant elephants for at least 6 million years. We discuss our results in the context of MHC diversity in other mammals and patterns of evolution in elephants.

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Divergent Patterns of Variation in Major Histocompatibility Complex Class Ii Alleles Among Antarctic Phocid Pinnipeds

Cited by 22 publications

References 42 publications

Low MHC DRB class II diversity in the mountain goat: past bottlenecks and possible role of pathogens and parasites

Low MHC DRB class II diversity in the mountain goat: past bottlenecks and possible role of pathogens and parasites

Survey for Selected Pathogens and Evaluation of Disease Risk Factors for Endangered Hawaiian Monk Seals in the Main Hawaiian Islands

Major histocompatibility complex variation and evolution at a single, expressed DQA locus in two genera of elephants

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