An overview of the mtDNA diversity across the Colombian Andean region

In Colombia, a country in the northwest corner of South America, populations are highly diverse due to the
intercontinental admixture of Native Americans, European settlers, and enslaved Africans. While genetic diversity
has been largely assessed based on autosomal markers, studies on mtDNA are much scarcer, allowing only
a fragmentary view of the distribution of maternal lineages in the country. In this study the genetic diversity of
maternal lineages in Colombian Andean populations was interrogated to infer whether the pattern of structuring
was in line with the different colonization histories of the departments within the region. The ultimate goal was
to establish a haplotype database for forensic purposes. In a total of 458 individuals born and residing in the
departments of the Andean region, haplotypes of the total mtDNA control region were determined and assigned
to the corresponding haplogroups. Across the 10 departments, haplotype diversities ranged between 0.9665 and
0.9967, and power of exclusion between 0.9208 and 0.9845. A component ascribed to be of Native American
ancestry prevailed in all departments, where 89.27 % of haplotypes in the total sample belonged to mtDNA
macro-haplogroups A2, B4, C1, and D. The remaining lineages were of Eurasian (6.65 %) or African (4.08 %)
origin. Pairwise FST values showed signs of genetic differentiation, but still only reached statistical significance
when Risaralda or Cundinamarca were compared with other populations. Principal component analysis showed
that the population structure was mainly due to some differences in Native American substrates. The results
obtained highlighted a heterogeneity within Andean populations that must be considered when developing
mtDNA haplotype databases for forensic purposes. In this context, the use of specific databases is recommended
for the departments of Risaralda and Cundinamarca, while the other departments can rely on a single haplotype
frequency database.