Diversification and subspecies patterning of the goitered gazelle (Gazella subgutturosa) in Iran

Abstract

Goitered gazelles, Gazella subgutturosa, exist in arid and semiarid regions of Asia from the Middle to the Far East. Although large populations were present over a vast area until recently, a decline of the population as a result of hunting, poaching, and habitat loss led to the IUCN classification of G. subgutturosa as “vulnerable." We examined genetic diversity, structure, and phylogeny of G. subgutturosa using mitochondrial cytochrome b sequences from 18 geographically distant populations in Iran. The median‐joining network of cyt b haplotypes indicated that three clades of goitered gazelles can be distinguished: a Middle Eastern clade west of the Zagros Mountains (and connected to populations in Turkey and Iraq), a Central Iranian clade (with connection to Azerbaijan), and an Asiatic clade in northeastern Iran (with connection to Turkmenistan, Uzbekistan, and other Asian countries as far as northeastern China and Mongolia). Based on our results, we argue that Iran is the center of diversification of goitered gazelles, due to the presence of large mountain ranges and deserts that lead to the separation of populations. In accordance with previous morphological studies, we identified the Asiatic clade as the subspecies G. s. yarkandensis, and the other two clades as the nominate form G. s. subgutturosa. The new genetic information for goitered gazelles in Iran provides the basis for future national conservation programs of this species.

Repeated hybridization of two closely related gazelle species (Gazella bennettii and Gazella subgutturosa) in central Iran

“…The phylogenetic analysis of complete cyt b sequences resolves G. subgutturosa and G. bennettii as sister species (Figure 4) as expected from previous studies (Abduriyim et al., 2018; Bärmann, Rössner, & Wörheide, 2013; Dong et al., 2016; Fadakar et al., 2019, 2020; Fadakar et al, 2013; Khosravi, Malekian, Hemami, Silva, & Brito, 2019; Lerp et al., 2016; Wacher et al., 2010). Samples from the central Iranian locations are either placed as G. bennettii or as G. subgutturosa (supposed hybrids).…”

“…With the current data, however, we conclude that the populations evolved independently after the initial hybridization events and that there was no back‐crossing with G. subgutturosa (at least not in the maternal line). Especially in northeastern Iran, it is interesting to see that the hybrid specimens have haplotypes (H68 and H69) that are only two to three mutational steps away from the proposed ancestral haplotype of the G. s. yarkandensis subspecies (H1, not present in Iran but reported from China (Fadakar et al., 2020)), but four to five steps away from the pure G. s. yarkandensis individuals (H49–H53) also living in Khorasan Province (Figure 3). So the natural hybridization occurred relatively early, probably when the subspecies were not even properly distinct.…”

“…These were previously sequenced for cyt b by Fadakar et al. (2020). The locality information, species identity, and the kind of material of all samples are summarized in Table 1.…”

“…A median‐joining (MJ) network was constructed for 295 sequences, including 16 new complete cyt b sequences from supposed hybrid individuals (this study), 60 sequences of G. subgutturosa from Iran (H49–H67 – Fadakar et al., 2020), and 219 published G. subgutturosa sequences from Asia (H1–H48 – Abduriyim, Nabi, & Halik, 2018; Dong et al., 2016; Hassanin et al., 2012; Hassanin & Douzery, 1999; Lerp et al., 2016) using the software PopART v.1.7 (Leigh & Bryant, 2015) with the default settings (Table , see Fadakar et al., 2020 for details of the alignment).…”

“…Due to the highly sculptured landscape, intraspecific patterning was detected in G. subgutturosa (Khosravi et al., 2018), where two subspecies were found to occur in Iran (Fadakar et al., 2020). G. bennettii was also supposed to split into at least two subspecies or even species in Iran (Groves & Grubb, 2011), but this has not been confirmed using molecular data yet.…”