Genetic diversity and novel haplotypes of Apis mellifera jemenitica on the Arabian Peninsula: insights from mtDNA markers

The genetic diversity of <i>Apis mellifera jemenitica</i> populations collected from the Arabian Peninsula (Saudi Arabia, Yemen, and Oman), Jordan, and Ethiopia, was examined using three mtDNA markers: 1- Cytochrome <i>b</i> (Cyt <i>b</i>), 2- Cytochrome <i>c</i> oxidase I (COI) and 3- The intergenic region located between the cytochrome <i>c</i> oxidase I & II (COI-COII). DNA was extracted from 44 samples, amplified for each region using classic PCR, and the resulting amplicons were sequenced using Sanger technology at both ends. Sequences were verified and aligned, and Maximum-Likelihood phylogenetic analyses were conducted with reference sequences from other subspecies. The <i>in silico</i> DraI mtDNA COI-COII (DmCC) test was applied to the COI-COII sequences to identify evolutionary lineages and haplotypes. Moreover, COI-COII haplotype network analyses were conducted to assess the intra- and inter-genetic relationships between samples and references. Based on the Cyt <i>b</i> marker, most samples cluster within the African lineage (A) near <i>lamarckii</i> and <i>syriaca</i> (Sub-lineage Z) subspecies. Few samples from Ethiopia and Yemen were closely related to <i>simensis</i> and <i>scutellata</i> clades. The COI gene separated <i>jemenitica</i> samples (Bootstrap = 97) from subspecies of other lineages (C and O). The DmCC test revealed a P0Q2 structure in the intergenic region for all samples, with a distinct 18 bp deletion in the P0 element observed in two Ethiopian and one Yemeni samples, suggesting <i>litorea</i> or <i>simensis</i> origin. A total of 13 COI-COII haplotypes were identified, among which 8 haplotypes were novel: Saudi Arabia (1), Yemen (3), Oman (1), and Ethiopia (3), with a haplotype diversity (<i>H</i>) of 0.980. Furthermore, molecular-variance parsimony in COI-COII confirmed a distant genetic relationship between Ethiopian samples versus samples of the Arabian Peninsula. The haplotype network analysis suggests a higher intra-<i>jemenitica</i> diversity than previously understood with a <i>syriaca</i> ancestry to this clade. These findings offer crucial insights into the conservation of <i>A</i>. <i>m</i>. <i>jemenitica</i> and its role in preserving biodiversity in arid ecosystems. Additionally, the data enhance our understanding of the genetic diversity of <i>A. m. jemenitica</i> and its evolutionary connections with other neighboring African subspecies.