Y-chromosome analysis in Retuertas horses

Area of Science:

• Genetics
• Zoology
• Animal Breeding

Background:

• The origins of horse domestication are debated, with conflicting data from mitochondrial DNA and Y-chromosome studies.
• Previous Y-chromosome research focused on common breeds, potentially missing genetic diversity in local or feral populations.
• The Retuertas horse, an ancient feral population in Spain, may preserve unique genetic information.

Purpose of the Study:

• To investigate the Y-chromosome genetic diversity of the Retuertas horse, an ancient feral population.
• To compare the Retuertas horse Y-chromosome data with other Iberian and global breeds.
• To assess the accuracy of existing Y-chromosome reference sequences in public databases.

Main Methods:

• Sequencing of 31 introns, the Zinc finger Y-chromosomal protein (ZFY) gene, and anonymous Y-linked fragments.
• Genotyping of 6 Y-chromosome microsatellite loci.
• Comparative analysis of Retuertas horse DNA with 11 regional and 15 global breeds.

Main Results:

• No sequence variation was found in the Y-chromosome among all analyzed individuals and breeds.
• Fifteen differences were identified between the study's data and existing GenBank reference sequences.
• These discrepancies suggest potential errors in the deposited reference sequences.

Conclusions:

• The horse Y-chromosome exhibits extremely low genetic variability across diverse populations.
• Existing public Y-chromosome reference sequences may contain errors and should be used cautiously.
• Further research is needed to clarify the full extent of Y-chromosome diversity in horses.