Iran's population is diverse in terms of ethnicity, language and religion, and also intermarriages are more common in some areas (Regueiro, Cadenas et al., 2006). On the other hand, the presence of geographical barriers, such as the Kavir desert in the central north, the lut desert in the east of the Iranian plateau, and the mountain ranges surrounding Alborz and Zagros contributes to obstacles to the gene flow through the land of the Persians to other parts of the world that they are one of the reasons for Iranians, making them unique(Bahmanimehr, Nikmanesh et al., 2014). Y-STR markers in different regions of Iran, including Tehran (Nasidze, Schädlich et al., 2003; Salimi, Farazmand et al., 2010), Mazandaran and Gilan (Sayyari, Salehzadeh et al., 2019), Golestan (Sayyari, Salehzadeh et al., 2020), Isfahan (Nasidze, Schädlich et al. 2003, Vatandoost, Salehi et al. 2017), Eastern provinces, such as Razavi Khorasan, South Khorasan, and Sistan and Baluchestan (Tabrizi, Hedjazi et al. 2015)have been already characterized. Given the unique geographical composition and diversity of the Iranian population, Y-STR markers in a large sample size among Iranians have not been widely studied. Such studies have a significant effect on enriching information for the use on a local and global scale. This was first study conducted on a large sample size among Iranians and provided information on the genetic polymorphisms of 17 Y-STR alleles .
Our resutls showed that the value of genetic diversity ranged from 0.340 (DYS391 in Tabriz) to 0.873 (DYS385a in Mazandaran). The highest polymorphic content in the Iranian population was observed in DYS385a, while the lowest polymorphic STRP marker was found in DYS391Also, the mean gene diversity in the Iranians was 0.685 that all they were the similar distribution to previously studied populations attributed to different regions of Iran (Tabrizi, Hedjazi et al., 2015; Sayyari, Salehzadeh et al., 2019; Sayyari, Salehzadeh et al., 2020).
The average gene diversity (GD) from neighboring countries, Eastern Turkey (Tokdemir and Tunçez, 2017), Turkish Cypriots (Teralı, Zorlu et al., 2014), and Pakistan populations (Mohyuddin, Ayub et al., 2001) was similar to Iranian population that might due to the geographical proximity of the place of residence of this population to Iran (as a result of the possibility of continued interbreeding between the people of the populations) or higher ethnic and racial proximity of this population to Iranians (preserving common ancestral markers).
The haplotype diversity was 1.00000, but the values of haplotype diversity in various areas of Iran, such as Tehran, Gilan, Mazandaran, Golestan, Isfahan, and eastern provinces were 0.997, 0.9998, 0.9993, 0.9962, 0.997, 0.9999, respectively. Moreover, the values of haplotype diversity from neighboring populations were 0.9850 in Afghanistan (Lacau, Bukhari et al., 2011), 0.9992 in Turkish Cypriots (Teralı, Zorlu et al., 2014), 0.99885 in United Arab Emirates (Alhammadi, Alghafri et al., 2017), 0.9986 in Eastern Turkey (Tokdemir and Tunçez, 2017), 0.999677 in Sindhi population of Pakistan (Perveen, Shahid et al. 2017), 0.9305 in Punjab Pakistan (Aslam, Hussain et al., 2020), 0.892 in Iraq (Kareem, Jebor et al., 2015), 0.9932 in Tunis (Ayadi, Ammar-Keskes et al., 2006), 0.9963 in German (Kayser, Krawczak et al., 2001), 0.9941 in Italy (Kayser, Krawczak et al., 2001), 0.9968 in China (Kayser, Krawczak et al., 2001), 0.996 in India (Kayser, Krawczak et al., 2001), and 1.0 in Qatar (Almohammed, Alghafri et al. 2015). The lower value of HD obtained for these countries demonstrated that there was less migration to the Iranian population. On the other hand, Iranian men living in Iran is isolated. The discriminating capacity obtained for the Iranians was 0.997 that was higher than that in different regions of Iran, including Tehran (DC = 0.9) (Nasidze, Schädlich et al., 2003), Isfahan (DC = 0.938 and DC = 0.95) (Nasidze, Schädlich et al., 2003; Vatandoost, Salehi et al.; 2017), Golestan (DC = 0.8207) (Sayyari, Salehzadeh et al., 2020), and the eastern provinces located in Iran (DC = 0.9884) (Tabrizi, Hedjazi et al. 2015) which the value of DC obtained for throughout Iran was higher than that for other provinces that difference in the value of DC between our population and other different regions of Iran might be attributed to the small size of the population examined in the previous studies.
Comparing the value of DC in Iranian population with that in neighboring populations, including, Afghanistan (DC = 0.6277) (Lacau, Bukhari et al., 2011), Turkish Cypriots (DC = 0.9051 ), Eastern Turkey (DC = 0.9343) (Tokdemir and Tunçez, 2017), United Arab Emirates (DC = 0.9003) (Alhammadi, Alghafri et al., 2017), Punjab Pakistan (DC = 0.6438) (Aslam, Hussain et al., 2020), Tunis (DC = 0.7714) (Ayadi, Ammar-Keskes et al. 2006), India (DC = 0.8497) (Shrivastava, Gupta et al., 2016), demonestrated that the Iranian population consisted of a relatively large number of unique haplotypes.
Population pairwise comparisons for analyzing different regions of Iran using haplotypes in this study and Iranian haplotypes registered in YHRD database showed that an insignificant difference was observed between them and the same results of close associations between the majority of the other socio-geographical populations within Iran, except for Masal, Izeh, indicating low genetic distance with other regions of Iran. We compared Iranian population with the data obtained from neighboring populations which are accessible in YHRD database and the statistical analysis revealed Afghanistan (FST = 0. 0027, P = 0.00), Pakistan (FST = 0. 0003, P = 0.00), Turkey (FST = 0. 0001, P = 0.00), Azerbaijan Republic (FST = 0. 0003, P = 0.00), Iraq (FST = 0. 0004, P = 0.00), and the United Arab Emirates (FST = 0. 0008, P = 0.00), Bahrain (FST = 0. 0014, P = 0.00), Egypt (FST = 0. 0008, P = 0.00), Kazakhstan(FST = 0. 0037, P = 0.00), Kuwait (FST = 0. 0018, P = 0.00), Lebanon(FST = 0. 0014, P = 0.00), Mongolia (FST = 0. 0031, P = 0.00), Russian Federation(FST = 0. 0003, P = 0.00), Qatar (FST = 0. 0015, P = 0.00) and Yemen (FST = 0. 0007, P = 0.00).
A comparison of the Iranian population with neighboring populations demonstrated that there were the significant genetic differences which might be due to geographical verities and ethnic differences. Also, it elucidated that these markers had the capability of male identity among the Iranian population. An AMOVA analysis of the different regions of Iran for 17 Y-STR haplotypes obtained from this study comparing with data from some of the neighboring populations (Supplementary Table 4) indicated that Turkey, Pakistan, and Iraq showed small genetic discrimination and evidence of a common ancestral lineage between populations living in this close regions. Also, Multidimensional scaling (MDS) plot based on pairwise Fst values between the study population and neighboring populations in YHRD database showed that the nearest genetics distance was observed between Turkey and Iran that was geographically close each other.
Y-STR haplotypes in the Iranian population had very close similarities Given this genetic similarity; it was not possible to draw the Multidimensional scaling (MDS) plot between different units of the Iranian population. For some Iranian regions and cultures, intermarriage is customary, and this was a limitation for us to take samples from unrelated Iranian males to evaluate the haplotype of the Y chromosome.