Mounir Abi Said

Genetic structure in village dogs reveals a Central Asian domestication origin

Significance Dogs were the first domesticated species, but the precise timing and location of domestication are hotly debated. Using genomic data from 5,392 dogs, including a global set of 549 village dogs, we find strong evidence that dogs were domesticated in Central Asia, perhaps near present-day Nepal and Mongolia. Dogs in nearby regions (e.g., East Asia, India, and Southwest Asia) contain high levels of genetic diversity due to their proximity to Central Asia and large population sizes. Indigenous dog populations in the Neotropics and South Pacific have been largely replaced by European dogs, whereas those in Africa show varying degrees of European vs. indigenous African ancestry. Dogs were the first domesticated species, originating at least 15,000 y ago from Eurasian gray wolves. Dogs today consist primarily of two specialized groups—a diverse set of nearly 400 pure breeds and a far more populous group of free-ranging animals adapted to a human commensal lifestyle (village dogs). Village dogs are more genetically diverse and geographically widespread than purebred dogs making them vital for unraveling dog population history. Using a semicustom 185,805-marker genotyping array, we conducted a large-scale survey of autosomal, mitochondrial, and Y chromosome diversity in 4,676 purebred dogs from 161 breeds and 549 village dogs from 38 countries. Geographic structure shows both isolation and gene flow have shaped genetic diversity in village dog populations. Some populations (notably those in the Neotropics and the South Pacific) are almost completely derived from European stock, whereas others are clearly admixed between indigenous and European dogs. Importantly, many populations—including those of Vietnam, India, and Egypt—show minimal evidence of European admixture. These populations exhibit a clear gradient of short-range linkage disequilibrium consistent with a Central Asian domestication origin.

Reply to Wang et al.: Sequencing datasets do not refute Central Asian domestication origin of dogs

We welcome the additional data and analyses of Wang et al. (1), but believe there are some misunderstandings regarding the methods and findings of Shannon et al. (2). First, although we merged Nepal and Mongolia when plotting linkage disequilibrium (LD) decay in figure 5B of ref. 2 for legibility, we did not assume Nepal and Mongolia represented a single, interbreeding population, and indeed computed separate LD scores for each population (figure 5A of ref. 2), matching Wang et al.’s (1) observation of slightly lower LD in Nepal than Mongolia. Although Nepal (along with India) is commonly considered part of South Asia, Nepal borders Central Asia. Dog populations in two Central Asian countries, Mongolia and Afghanistan, both have lower LD than India. Nepal does not border Southeast Asia. Because we cannot, given the resolution of current sampling … [↵][1]1To whom correspondence should be addressed. Email: arb359{at}cornell.edu. [1]: #xref-corresp-1-1

Sustainable Improvement of Small Ruminant Production in the Semi-Arid Areas of Lebanon

ABSTRACT Small ruminant production in semi-arid areas could be improved drastically by overcoming feed, health and management constraints. This study aimed at assessing the bio-economical sustainability of small ruminant production in the semi-arid regions of Lebanon through the introduction of an integrated technical package including: a basic health preventive program, feed optimization during critical late gestation period and finally, a basic selection program. Seventeen herders were divided into four groups: Groups A and B were given the full technical package with either soybean and corn meal or barley supplements, respectively. Group C received a basic preventive health program only and Group D was considered the control group. Bio-economic data were collected on a monthly basis over one year and submitted to a cost benefit analysis. Feed cost and pasture rent represented the major obstacles to productivity and contributed 53% and 33%, respectively, to the total financial cost. Groups A and B showed better financial revenues than groups C and D, with Group A having the highest return and lowest risk in terms of total expenditure and total revenue variances. It may be concluded that the integration of preventive health, feed optimization, and basic selection into one program could improve the economical sustainability of small ruminant production systems in semi-arid areas.