Comparative genomics reveals common diversity and adaptation to harsh
environments in the Arabian Peninsula indigenous chickens
Abstract
Identifying genomic regions under selection is crucial for comprehending
the evolutionary history of the domestic chicken. The Arabian Peninsula
(AP) indigenous chickens are mostly found outdoors, being reared
alongside other livestock for production purposes. These birds show high
resilience to extreme temperatures (hot and cold), typical of the desert
environment. The selection pressures responsible for unique local
adaptations in these birds remain largely unidentified. Here, we aimed
to investigate the genome diversity and structure of fifteen indigenous
chicken populations including thirteen populations from the AP (n = 5),
Ethiopia (n = 6), and the Republic Popular of China (n = 2). We also
included two commercial chicken populations, Fayoumi (selected for heat
tolerance) and Chantecler (known for its cold tolerance). The PCA
separated all the populations based on their geographic areas of origin.
PC1 separates the Ethiopian populations from the Chinese and AP
populations. PC2 separates the AP populations from the Chantecler, and
the Ethiopian populations from the Dulong (China) and Chantecler. The
genome-wide signatures of analyses identified many candidate regions
under positive selection. They include genes which may be associated
with thermotolerance. These are involved in energy balance and
metabolism ( SUGCT, HECW1, MMADHC), cells apoptosis (
APP, SRBD1, NTN1, PUF60, SLC26A8, DAP, SUGCT),
angiogenesis ( RYR2, LDB2, SOX5), skin protection to solar
radiation ( FZD10, BCO2, WNT5B, COL6A2 and SIRT1)
as well as growth ( NELL1). Our findings suggest that Arabian
chicken populations have a distinct gene pool polymorphism in relation
to their adaptation to the harsh climatic environments of the Arabian
Peninsula.