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R.Rocca
06-13-2014, 02:55 PM
Increasing phylogenetic resolution of haplogroup U in Iberia through mtDNA complete sequencing

http://forensischinstituut.be/upload/images/DNA%20abstract%20book%20light.pdf

Human mtDNA has become an important genetic system in different fields, such as population, medical and forensic genetics, due to its unique characteristics, high copy number per cell and a maternal mode of inheritance, among others.

Accompanying the advances of the molecular biology techniques, the forensic filed has increased the detail of the analysis of mtDNA variation. Currently, sequencing of the hypervariable segments within the mtDNA control region is considered the standard analysis. However, complete sequences are more and more necessary to establish a correct phylogenetic assignment and for quality control of novel mtDNA data, although not yet routinely used in forensic casework.

In Western Europe and particularly in Iberia, the primary target for complete mtDNA analysis has been the most frequent (~40%) clade, H, particularly its sub-clades H1 and H3, because of the need to increase their phylogenetic resolution. However, other relevant haplogroups account for the mtDNA diversity of this geographic region. The second most frequent haplogroup is U (~10%), but at present there is a lack of complete haplogroup U sequences from Iberia in the available public databases.

In this work, we performed complete mtDNA Sanger sequencing of 35 U4 and U5 samples in 9 overlapping amplified fragments. Samples were selected from a previous analysis of 349 mtDNA control region samples from continental Portugal, where 10% of the diversity was found to belong to sub-haplogroups U4 (1.4%) and U5 (8.6%). We here present the complete genome sequences and analyse the increase in phylogenetic resolution of the mtDNA tree obtained for sub-haplogroups U4 and U5 in the Iberian peninsula.