Genetic Differentiation among Livestock Breeds-Values for F_st

Area of Science:

• Population Genetics
• Animal Breeding
• Genomics

Background:

• The Fst statistic quantifies genetic differentiation between populations.
• A threshold of Fst = 0.1 is often used to define distinct breeds.
• This study questions the universal applicability of the Fst = 0.1 threshold.

Purpose of the Study:

• To evaluate the appropriateness of the Fst = 0.1 threshold for assessing livestock breed distinctiveness.
• To analyze the variability of Fst values across diverse livestock species and breeds.

Main Methods:

• Compilation of a large database (35,080 pairs) of Fst values from microsatellite and SNP studies.
• Inclusion of data from cattle, sheep, goats, pigs, horses, and chickens.
• Categorization of breed pairs by geographic proximity and species' wild ancestors.

Main Results:

• Fst values exhibit considerable variability across species and marker types (microsatellite vs. SNP).
• Observed Fst ranges often exceed or encompass the 0.1 threshold, indicating overlap and inconsistency.
• Specific ranges provided for cattle, sheep, horses, goats, pigs, and chickens.

Conclusions:

• The Fst = 0.1 threshold is not a universally appropriate measure for livestock breed distinctiveness due to high variability.
• A substantial body of Fst data exists for global livestock breeds.
• Fst data holds potential for interdisciplinary research in animal genetics and breeding.