Feline immunodeficiency virus (FIV), a feline lentivirus related to HIV, causes immune dysfunction in domestic and wild cats. The Pallas cat is the only species from Asia known to harbor a species-specific strain of FIV designated FIV(Oma) in natural populations. Here, a 25% seroprevalence of FIV is reported from 28 wild Mongolian Pallas cats sampled from 2000 to 2008. Phylogenetic analysis of proviral RT-Pol from eight FIV(Oma) isolates from Mongolia, Russia, China and Kazakhstan reveals a unique monophyletic lineage of the virus within the Pallas cat population, most closely related to the African cheetah and leopard FIV strains. Histopathological examination of lymph node and spleen from infected and uninfected Pallas cats suggests that FIV(Oma) causes immune depletion in its native host.
The ?(15)N values of organisms are commonly used across diverse ecosystems to estimate trophic position and infer trophic connectivity. We undertook a novel cross-basin comparison of trophic position in two ecologically well-characterized and different groups of dominant mid-water fish consumers using amino acid nitrogen isotope compositions. We found that trophic positions estimated from the ?(15)N values of individual amino acids are nearly uniform within both families of these fishes across five global regions despite great variability in bulk tissue ?(15)N values. Regional differences in the ?(15)N values of phenylalanine confirmed that bulk tissue ?(15)N values reflect region-specific water mass biogeochemistry controlling ?(15)N values at the base of the food web. Trophic positions calculated from amino acid isotopic analyses (AA-TP) for lanternfishes (family Myctophidae) (AA-TP ?2.9) largely align with expectations from stomach content studies (TP ?3.2), while AA-TPs for dragonfishes (family Stomiidae) (AA-TP ?3.2) were lower than TPs derived from stomach content studies (TP?4.1). We demonstrate that amino acid nitrogen isotope analysis can overcome shortcomings of bulk tissue isotope analysis across biogeochemically distinct systems to provide globally comparative information regarding marine food web structure.
The ABO histo-blood group, the critical determinant of transfusion incompatibility, was the first genetic polymorphism discovered in humans. Remarkably, ABO antigens are also polymorphic in many other primates, with the same two amino acid changes responsible for A and B specificity in all species sequenced to date. Whether this recurrence of A and B antigens is the result of an ancient polymorphism maintained across species or due to numerous, more recent instances of convergent evolution has been debated for decades, with a current consensus in support of convergent evolution. We show instead that genetic variation data in humans and gibbons as well as in Old World monkeys are inconsistent with a model of convergent evolution and support the hypothesis of an ancient, multiallelic polymorphism of which some alleles are shared by descent among species. These results demonstrate that the A and B blood groups result from a trans-species polymorphism among distantly related species and has remained under balancing selection for tens of millions of years-to date, the only such example in hominoids and Old World monkeys outside of the major histocompatibility complex.
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