Desert-Edge Contact Zone Between Goitered Gazelle Subspecies in Northeastern Iran

The vulnerable goitered gazelle (Gazella subgutturosa) comprises two evolutionarily distinct subspecies in Iran, separated by the central deserts as biogeographic barriers: G. s. yarkandensis (northeast) and G. s. subgutturosa (elsewhere). Using mitochondrial cytochrome b (307 sequences) and nuclear markers (CHD2, ZNF618), we resolved subspecies status in understudied northeastern Iran. Results confirmed G. s. yarkandensis predominance but revealed two pure G. s. subgutturosa haplotypes (H70, H78) through combined genetic analyses. H70 was previously associated with hybrids in central Iran, while H78 was novel. Phylogenetically, both clustered within the G. s. subgutturosa clade adjacent to hybrid haplotypes, with H78 one mutation from H70. Nuclear diagnostics confirmed subspecies identity, rejecting hybrid origins. Critically, H78 occurred naturally at Eshqabad No Hunting Area (northeastern Dasht-e Kavir edge), with H70 at Qayen Breeding Center (translocated). This identifies the northeastern edge of the Dasht-e Kavir as a contact zone where G. s. subgutturosa likely traverses the central deserts into northeastern Iran, overlapping with predominant G. s. yarkandensis. This contact may be facilitated by the latter's westward range expansion from Central Asia. Desert-edge habitats are thus vital conservation priorities, requiring genetic monitoring to maintain subspecies integrity and secure prey for the critically endangered Asiatic cheetah (<50 individuals).