Analysis of Population Structure and Selection Signature in Wadi Sheep Based on Resequencing Data
Simple Summary The Wadi sheep (WAD) is an important local breed in Shandong Province, China. It is well known for its adaptability to humid and saline–alkali lowland environments and has been reported to show disease resistance and year-round reproductive activity. However, the population of purebred WAD has declined in recent decades because of the widespread introduction of other sheep breeds, threatening the long-term preservation of its unique genetic resources. In this study, we used whole-genome data to investigate the genetic characteristics of WAD and compared it with several other breeds. Our results showed that WAD still maintains a relatively high level of genetic diversity and forms a clearly separate genetic group, reflecting its unique breeding history. We also identified many genomic regions shaped by long-term natural and human-driven selection. These regions contain genes potentially related to environmental adaptation, immune defense, muscle traits, growth, and reproduction. These findings suggest possible genomic adaptation of WAD to challenging lowland environments and provide valuable guidance for its conservation and future breeding efforts.