Paternal heritage in Jujuy province (Northwest Argentina): Evidence for sex‐biased gene flow and genetic drift effects

OBJECTIVES: This study aimed to explore the diversity of paternal lineages in Jujuy province (Argentina) by analyzing Y chromosome markers. Furthermore, we examined among-population genetic variability based both on paternally (NRY haplotypes) and maternally (mtDNA haplogroups) inherited markers. We sought to evaluate the impact of sex-biased gene flow on genetic background in Jujuy, and contribute data on the microevolutionary forces acting in this zone. METHODS: DNA from 149 males from five Jujuy regions were analyzed for 12 non-recombining Y (NRY) markers. Genetic heterogeneity among Jujuy regions was evaluated through population differentiation tests. To identify potential genetic boundaries in Jujuy, analysis of molecular variance (AMOVA) and the Monmonier's algorithm implemented in the Barrier v2.2 software were employed. RESULTS: A clear divergence between Jujuy highlands and lowlands for NRY haplotypes was found. A marked discrepancy between genetic structuring for paternal lineages and the lack of geographical pattern for mitogenomes was confirmed by all statistical analyses. CONCLUSIONS: Genetic structuring of paternal lineages is most likely caused by admixture processes that have occurred since colonial times in the Jujuy lowlands. Immigrants were predominantly male that settled in the lower altitude zones, due to the steep orography of the region. Input of allochthonous male lineages because of gene flow toward the lowlands would have increased diversity of NRY markers, thus compensating for drift effects. Likewise, limited input of allochthonous mitogenomes would have promoted genetic drift, a key factor in the shaping of diversity of maternal lineages across Jujuy subpopulations, irrespective of altitude.