An approach to maternal ancestry in a sample of Ecuadorian “mestizo” population by sequencing the control region of mtDNA

Abstract

Mitochondrial DNA analysis has proven to be a powerful tool to study maternal inheritance among populations. It is also useful to infer geographical origin and relationships between individuals and population samples. In this study, mtDNA control region was sequenced from 54 self-declared Ecuadorian mestizos. Haplotype diversity (0.9986 +/-0.0039) and mean number of pairwise differences (17.586303 +/-7.933894) were high, in accordance to previous studies. Around 96% of the analyzed individuals had Native American maternal lineages. Based on genetic distances, Ecuador showed significant differences with other South American populations, except in the comparison with another sample from Ecuadorian mestizos, as expected.

Investigating genetic diversity in admixed populations from Ecuador

“…Although a 26% European contribution was reported by (Zambrano et al, 2019) for autosomal markers, no signs of European admixture were detected in the Amazonian population for the X‐chromosomal indels. These results indicated a lower maternal than paternal European contribution, which is consistent with published data from nonrecombining genomes (Baeta et al, 2012; Burgos, Garzón‐Salazar, et al, 2019; Burgos, Simão, et al, 2019; Toscanini et al, 2018). Previous studies comparing mtDNA and Y chromosome data, apart from differences among Ecuadorian Mestizo populations, also revealed clear sex‐biased mating processes, involving predominantly descendants from European men and Native American women.…”

“…Previous studies comparing mtDNA and Y chromosome data, apart from differences among Ecuadorian Mestizo populations, also revealed clear sex‐biased mating processes, involving predominantly descendants from European men and Native American women. Regarding maternal inheritance, the available studies show that most Ecuadorian Mestizo populations present a set of mtDNA lineages that are mainly of Native American ancestry (above 96%) (Baeta et al, 2012; Burgos, Garzón‐Salazar, et al, 2019; Burgos, Simão, et al, 2019). In contrast, Y‐chromosomal lineages are primarily European (above 55%), although populations still retain a significant part of their ancient paternal ancestry (between 26% in the Pacific coast and 44% in Amazonia) (Burgos, Garzón‐Salazar, et al, 2019, Burgos, Simão, et al, 2019, Toscanini et al, 2018).…”

“…To capture the genetic diversity present in current populations of Ecuador, several studies have been developed focusing on different population groups and different regions of the genome (Baeta et al, 2009, 2012; Baeza et al, 2007; Burgos, Garzón‐Salazar, et al, 2019; Burgos, Simão, et al, 2019; Cardoso et al, 2012; González‐Andrade et al, 2006; González‐Andrade et al, 2008; González‐Andrade et al, 2009; Santangelo et al, 2017; Toscanini et al, 2018; Zambrano et al, 2017, 2019). Studies using autosomal ancestry informative markers (AIMs) showed that admixed populations in Ecuador (Mestizos) preserve a significant Native American ancestry, followed by European and African contributions (Poulsen et al, 2011; Santangelo et al, 2017; Zambrano et al, 2017, 2019).…”

“…Native American ancestry is higher in Amazonia, followed by the Andes and has the lowest value on the Pacific coast (Toscanini et al, 2018). However, paternal European inheritance is predominant in all Mestizo groups (Burgos, Garzón‐Salazar, et al, 2019; Burgos, Simão, et al, 2019; Toscanini et al, 2018). In contrast, the mtDNA lineages are mainly of Native American ancestry (Baeta et al, 2012; Burgos, Garzón‐Salazar, et al, 2019; Burgos, Simão, et al, 2019).…”