High connectivity among argali sheep from Afghanistan and adjacent countries: Inferences from neutral and candidate gene microsatellites

Abstract

We quantified population connectivity and genetic variation in the Marco Polo subspecies of argali mountain sheep (Ovis ammon polii) by genotyping 9 neutral and 8 candidate gene microsatellite loci in 172 individuals noninvasively sampled across five study areas in Afghanistan, China, and Tajikistan. Heterozygosity and allelic richness were generally high (mean H = 0.67, mean A = 6.1), but were significantly lower in the China study area (H = 0.61, P \ 0.001; A = 4.9, P \ 0.01). One marker in an immune system gene (TCRG4) showed an excess of rare alleles compared to neutral expectations. Another immune system gene (GLYCAM-1) showed excessive differentiation (high F ST ) between study areas. Estimates of genetic differentiation were similar (F ST = 0.035 vs. 0.033) with and without the two loci deviating from neutrality, suggesting that selection is not a primary driver of overall molecular variation, and that candidate gene loci can be used for connectivity monitoring, as long as selection tests are conducted to avoid biased gene flow estimates. Adequate protection of argali and maintenance of inter-population connectivity will require monitoring and international cooperation because argali exhibit high gene flow across international borders.

A tale of two markers: Population genetics of colorado rocky mountain bighorn sheep estimated from microsatellite and mitochondrial data

“…Estimating heterozygosity is therefore important because positive correlations between heterozygosity and both fitness (FitzSimmons et al ) and resistance to disease have also been documented in bighorn sheep (Coltman et al , Luikart et al ). We found estimated heterozygosities in the RMNP herds to be comparable to the highest values reported in other studies of native bighorn sheep populations (Boyce et al , Forbes and Hogg 1999, Epps et al , Johnson et al , Luikart et al ) and higher than those reported for some restored bighorn sheep populations (Whitaker et al , Olson et al ). Our inbreeding coefficient estimates support these heterozygosity estimates in that we did not detect a significant loss of heterozygosity, as indicated by a large positive F is .…”

“…Each run included 10,000 iterations and we evaluated the data under 7 different model parameter combinations: TPM with 5% IAM and variance of 12, TPM with 5% IAM and variance of 30, TPM with 10% IAM and variance of 12, TPM with 10% IAM and variance of 30, TPM with 20% IAM and variance of 12, TPM with 20% IAM and variance of 30, and a strict SMM model. We selected these parameter combinations based on author recommendations (Piry and Cornuet 1999) and previous work on bighorn sheep (Ramey , Ramey et al , Luikart et al ). We evaluated allele frequency distributions graphically via a qualitative mode‐shift indicator of bottlenecked populations identified by a disproportionate loss of rare alleles.…”

Bighorn sheep gut microbiomes associate with genetic and spatial structure across a metapopulation

“…Three of the 16 markers used in the Rousset's a calculations were excluded from the expected heterozygosity estimation, because these markers were suspected to be linked with potentially adaptive alleles [43][44][45]. Although these three loci were shown to behave neutrally 37,46,47 we chose to exclude these markers from the expected heterozygosity analysis to avoid any cryptic selective influences on heterozygosity metrics. Heterozygosity estimates using a similar number of microsatellite loci have been shown to correlate with population isolation 35 , elevation 34 , and NDVI 32 in the Mojave Desert bighorn sheep metapopulation.…”

Status and population structure of a hunted population of Marco Polo Argali Ovis ammon polii (Cetartiodactyla, Bovidae) in Southeastern Tajikistan

“…Because some segment of the population may be moving through the study area in fall and winter, and surveys are not conducted during the same dates every year, differences in abundance among years may be obtained. Genetic evidence and direct observations indicate connectivity between the Marco Polo sheep populations of Afghanistan and Tajikistan (Luikart et al 2011, Rosen 2012. Large numbers of wild sheep are known to occur adjacent to our study area in Tajikistan.…”