Mitochondrial DNA control-region and coding-region data highlight geographically structured diversity and...

Area of Science:

• Genetics
• Zoology
• Animal Science

Background:

• Donkeys (Equus asinus) have played a vital role in agriculture and transport for millennia.
• Mechanization has led to declining donkey populations and erosion of genetic diversity.
• Understanding donkey genetic diversity is crucial for conservation efforts.

Purpose of the Study:

• To assess worldwide donkey mitochondrial DNA (mtDNA) diversity.
• To evaluate geographical patterns of variation in donkey populations.
• To establish a new nomenclature for donkey mtDNA haplogroups.

Main Methods:

• Analysis of coding-region data from 164 complete mitogenomes.
• Examination of 1392 donkey mtDNA control-region sequences.
• Phylogenetic network analysis and AMOVA to study geographical distribution of variation.

Main Results:

• Confirmed two major clades (now haplogroup A and B) and identified a deep-diverging lineage within Clade 2.
• North-eastern Africa identified as the likely domestication center based on diversity and expansion metrics.
• Co-occurrence of both haplogroups in sampled populations, with regional variations influenced by demography and human migration.

Conclusions:

• Significant mtDNA variability exists in donkeys, underscoring the need for conservation.
• The identification of an early radiating lineage warrants further investigation.
• A comprehensive characterization of donkey nuclear genome diversity is essential for identifying conservation hotspots and preserving local breeds.