title: Impact of Y chromosome AZFc subdeletion shows lower risk of fertility impairment in Siddi tribal men, Western Ghats, India.
abstract: BACKGROUND
  India is characterized by the presence of a large number of endogamous castes, tribes and religions, having second largest concentration of tribal population in the World with differed genetic ethnicity, lifestyle and environmental habitat from those of mainstream population. Lack of data is constraint when it comes to tracking the tribal population health status, specifically reproductive health aspects by experimental approaches. The male fertility impairment depends on Y chromosome azoospermia factor c (AZFc) subdeletions, which varies highly in different geographical populations and in an Indian admixed population the frequency and effect of deletion on fertility is relatively poorly documented. Therefore, the current study has been initiated to enumerate and characterize the strength of association between Yq11 AZFc subdeletions and fertility impairment among Siddi tribal men of Western Ghats, India.
  
  
  METHODS
  Here, using predesigned performa we collected personal as well as familial information of 200 volunteered male subjects and grouped them into: (i) 104 married individuals with proven fertility, and (ii) 96 unmarried men with unknown fertility status. Quantification of reproductive hormones such as follicle stimulating hormone (FSH), leutinizing hormone (LH) and testosterone were studied. Oxidative stress markers like total antioxidant capacity (TAC) and super oxide dismutase (SOD) along with analysis of five sequence tagged site (STS) hotspot markers were employed for mapping of Y chromosome AZFc subdeletions. Statistical analyses were performed using SPSS software.
  
  
  RESULTS
  Hormonal analysis and estimation of oxidative stress markers showed normal values with no significant differences between two subgroups. However, the Y chromosome AZFc subdeletion mapping revealed evident results as an individual displayed absence of STS sY1191 marker indicating b2/b3 deletion, whereas rest of the subjects exhibited no deletion for all the five STS markers. While, the individual has fathered two children, at this point it is difficult to draw a causal link between the observed deletion and its effect on fertility.
  
  
  CONCLUSIONS
  Thus, our current study suggests that the association between AZFc subdeletions with its effect on infertility varies highly in this study cohort compared to other Indian ethnic groups, exhibiting lower risk factor and non-association reaching insignificance among Siddi tribal men.
authors.affiliation: Molecular Reproductive and Human Genetics Laboratory, Department of Studies in Zoology, University of Mysore, Manasagangothri, Mysore, 570006 Karnataka India.
authors.forename: Shivaprasad Holenarasipura
authors.initials: SH
authors.lastname: Sathyanarayana
authors.affiliation: Molecular Reproductive and Human Genetics Laboratory, Department of Studies in Zoology, University of Mysore, Manasagangothri, Mysore, 570006 Karnataka India.
authors.forename: Suttur Srikanta Naik
authors.initials: SS
authors.lastname: Malini
keywords: Ethnicity; Male infertility; Siddi tribe; Subdeletions; Y chromosome