Tracing the Spread and Diversity of Modern Goats Across Europe, Africa, and Asia

Jim Crocker
28th July, 2024

Tracing the Spread and Diversity of Modern Goats Across Europe, Africa, and Asia

Key Findings

  • The study analyzed genetic data from 2881 goats across Europe, Africa, and Asia to understand genetic diversity patterns
  • Researchers found that genetic diversity in goats decreases as the distance from Ganj Dareh, an early domestication site in Iran, increases
  • This decline in genetic diversity supports the idea that the initial domestication and spread of goats led to a reduction in genetic diversity with increasing distance from the origin
Goat domestication, a pivotal event in the development of agriculture and human civilization, occurred in the Fertile Crescent around 10,000 years ago. This domestication process and subsequent spread across Eurasia and Africa have been subjects of considerable scientific inquiry. A recent study conducted by researchers at the Universitat Autònoma de Barcelona[1] provides new insights into the genetic diversity of modern goats and its correlation with their geographic distance from Ganj Dareh, a Neolithic settlement in western Iran. The study analyzed data from the AdaptMap project and other sources, encompassing 1077 European, 1187 African, and 617 Asian goats from a total of 103 different breeds. The researchers aimed to determine whether genetic diversity, measured by observed (Ho) and expected (He) heterozygosities, declines with increasing distance from Ganj Dareh, a known early site of goat domestication. Previous studies have already indicated that goat domestication was a complex process involving multiple wild goat sources and different regions within the Fertile Crescent[2]. These studies revealed that early domesticated goats exhibited significant genetic divergence, reflecting the diverse human populations that managed them. The new study builds on this understanding by providing a more detailed analysis of genetic diversity across a broader geographic range. The researchers found a significant correlation between genetic diversity and distance from Ganj Dareh. Specifically, they observed a gradient of declining genetic diversity in goat populations as one moves away from this early domestication center. This finding supports the hypothesis that the initial domestication and subsequent dispersal of goats led to a decrease in genetic diversity with increasing distance from the origin. This study also ties into earlier findings that suggest multiple domestication events and the influence of ancient wild goat populations on modern goats[3]. By analyzing genome-wide data from ancient and modern goats, previous research has shown that domesticated goats have undergone significant genetic changes, including selection for traits like pigmentation, stature, and reproductive capabilities. These changes were driven by human intervention and environmental adaptations over thousands of years. Moreover, the study aligns with research that highlights the importance of genetic introgression from wild relatives in shaping the genomes of domestic goats[4]. For instance, an ancient introgression event from a West Caucasian tur-like species introduced beneficial alleles into the goat genome, enhancing immune resistance and possibly influencing behavior. These introgressed genes became more prevalent as domesticated goats spread and adapted to new environments. The methodology employed in the current study involved the use of geographic coordinates and heterozygosity estimates to assess genetic diversity. Observed heterozygosity (Ho) refers to the proportion of individuals in a population that are heterozygous at a given locus, while expected heterozygosity (He) is the probability that two alleles randomly selected from the population will be different. By comparing these measures across different breeds and regions, the researchers could infer patterns of genetic diversity and their relationship to the distance from the domestication center. In conclusion, the study from the Universitat Autònoma de Barcelona provides robust evidence that the genetic diversity of modern goats decreases with increasing distance from Ganj Dareh. This finding adds to our understanding of the complex history of goat domestication and dispersal, corroborating earlier research on multiple domestication events and the genetic impact of ancient wild goats. The study's comprehensive analysis of genetic data across a wide geographic range underscores the enduring influence of early domestication centers on present-day livestock genetics.

GeneticsAnimal ScienceEvolution

References

Main Study

1) Investigating the footprint of post-domestication dispersal on the diversity of modern European, African and Asian goats

Published 27th July, 2024

https://doi.org/10.1186/s12711-024-00923-5

Related Studies

2) Ancient goat genomes reveal mosaic domestication in the Fertile Crescent.

https://doi.org/10.1126/science.aas9411

3) Domestication and early agriculture in the Mediterranean Basin: Origins, diffusion, and impact.

https://doi.org/10.1073/pnas.0801317105

4) The origin of domestication genes in goats.

https://doi.org/10.1126/sciadv.aaz5216


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