Mitochondrial DNA Control Region Polymorphism in the Population of Alagoas State, North‐Eastern Brazil

Abstract

The sequences of the two hypervariable (HV) segments of the mitochondrial DNA (mtDNA) control region were determined in 167 randomly selected, unrelated individuals living in the state of Alagoas, north-eastern Brazil. One hundred and forty-five different haplotypes, associated with 139 variable positions, were determined. More than 95% of the mtDNA sequences could be allocated to specific mtDNA haplogroups according to the mutational motifs. Length heteroplasmy in the C-stretch HV1 and HV2 regions was observed in 22 and 11%, respectively, of the population sample. The genetic diversity was estimated to be 0.9975 and the probability of two random individuals presenting identical mtDNA haplotypes was 0.0084. The most frequent haplotype was shared by six individuals. All sequences showed high-quality values and phantom mutations were not detected. The diversity revealed in the mitochondrial control region indicates the importance of this locus for forensic casework and population studies within Alagoas, Brazil.

A great diversity of Amerindian mitochondrial DNA ancestry is present in the Mexican mestizo population

“…It is noteworthy that most haplotypes (192; 95%) have not been reported earlier (Table 1). 27,39,[40][41][42] The haplotype diversity of the whole control region was 0.9945, with a mean number of pairwise differences of 11.14 and a nucleotide diversity of 0.0655 (see Table 2). Unlike HVR1, HVR2 had 15 sites that showed indels either as a singlepoint insertion (insertion at 180G) or as a part of polymorphic microsatellite (p248-249, p286-291, p303-309 and p311-315) and non-microsatellite (p106-111) tracts.…”

“…40 To evaluate the significance of differences in the proportion of mitochondrial haplogroups ancestry among the groups, a w 2 test was performed. The significance of comparison of the mean pairwise differences and the nucleotide diversity was evaluated using the Student's t-test.…”

“…Considering only the positions at HVR1, this haplotype has been reported earlier once in Latin America. [40][41][42] Interestingly, the polymorphism A16183C was identified in all haplogroup B2 sequences. The haplogroup B2 in this study was further divided in two subgroups, based on transversion A16182C, which was found in 54.1% of the B2 haplotypes.…”

“…Considering only the HVR1, this haplotype has been reported earlier in populations from Mexico and Latin America. 17,40 Although the adenine deletions in the poly-A tracts of HVR2 are characteristic of haplogroup C, they had been rarely reported in other haplogroups. 40,46 For instance, in Asian populations these deletions have been found in the haplogroups A, F and R9 instead.…”

“…HVR1 polymorphisms found in haplotype Mx7 (11.1% of all haplotypes when only HVR1 were considered) have been reported earlier in other studies but in lower proportions (5-8%). [39][40][41][42] From 93 haplotypes that composed the haplogroup A2, 77 had a thymine at position 16111 and only 16 had the cytosine similar to the rCSR. Before the classification suggested by Bandelt, 26 haplogroup A was split into A1 and A2 by the transition at this position.…”