Population Genomics and Structure of the Critically Endangered Mariana Crow (Corvus kubaryi).

The Mariana Crow, or Åga (Corvus kubaryi), is a critically endangered species (IUCN -International Union for Conservation of Nature), endemic to the islands of Guam and Rota in the Mariana Archipelago. It is locally extinct on Guam, and numbers have declined dramatically on Rota to a historical low of less than 55 breeding pairs throughout the island in 2013. Because of its extirpation on Guam and population decline on Rota, it is of critical importance to assess the genetic variation among individuals to assist ongoing recovery efforts. We conducted a population genomics analysis comparing the Guam and Rota populations and studied the genetic structure of the Rota population. We used blood samples from five birds from Guam and 78 birds from Rota. We identified 145,552 candidate single nucleotide variants (SNVs) from a genome sequence of an individual from Rota and selected a subset of these to develop an oligonucleotide in-solution capture assay. The Guam and Rota populations were genetically differentiated from each other. Crow populations sampled broadly across their range on Rota showed significant genetic structuring ⁻ a surprising result given the small size of this island and the good flight capabilities of the species. Knowledge of its genetic structure will help improve management strategies to help with its recovery.

Genetics and caging type affect birth weight in captive pigtailed macaques (Macaca nemestrina).

The heritability of birth weight was estimated in 3,562 captive pigtailed macaques using 30 years of breeding and pedigree records. Based on a pedigree of over 12,000 animals, quantitative genetic analyses were performed using statistical variance decomposition methods. The model included additive genetic effects, cytoplasmic genetic effects, birth environment, shared maternal environment, and unmeasured environmental effects. The results demonstrated a strong (h(2) = 0.51) heritable component of birth weight overall, and included significant additive genetic heritability (h(2) = 0.23), and cytoplasmic heritability (h(2) = 0.09). In addition, a significant effect of birth location and cage type was identified, explaining an additional 6% of birth weight variance. The use of a nonhuman primate model for studying the effects of genes on birth weight eliminated many of the problems associated with confounding variables in human studies, and allowed for the quantification of a heritable component of birth weight.