X-chromosome data for 12 STRs: Towards an Argentinian database of forensic haplotype frequencies.

The analysis of X-chromosome STRs is useful in certain kinship cases for which autosomal markers provide insufficient statistical power. Particularly, powerful results are achieved in paternity cases with a daughter, when the alleged father is not accessible for analysis, contrarily to his unquestioned mother or daughter. However, representative haplotype frequencies for this type of markers are not available for some populations, as is the case of Argentina, which prevents the quantification of the proof in routine forensic analyses. In this work we present haplotype frequencies for the 12 X-chromosome STRs included in the Investigator Argus X-12 kit, as well as segregation data, obtained from the analysis of the genetic profiles of 457 father-daughter duos, which gave us information on 914 (unrelated) haplotypes from residents of all Argentinian provinces.

Genetic variation among the Mapuche Indians from the Patagonian region of Argentina: mitochondrial DNA sequence variation and allele frequencies of several nuclear genes.

DNA samples from 60 Mapuche Indians, representing 39 maternal lineages, were genetically characterized for (1) nucleotide sequences of the mtDNA control region; (2) presence or absence of a nine base duplication in mtDNA region V; (3) HLA loci DRB1 and DQA1; (4) variation at three nuclear genes with short tandem repeats; and (5) variation at the polymorphic marker D2S44. The genetic profile of the Mapuche population was compared to other Amerinds and to worldwide populations. Two highly polymorphic portions of the mtDNA control region, comprising 650 nucleotides, were amplified by the polymerase chain reaction (PCR) and directly sequenced. The 39 maternal lineages were defined by two or three generation families identified by the Mapuches. These 39 lineages included 19 different mtDNA sequences that could be grouped into four classes. The same classes of sequences appear in other Amerinds from North, Central, and South American populations separated by thousands of miles, suggesting that the origin of the mtDNA patterns predates the migration to the Americas. The mtDNA sequence similarity between Amerind populations suggests that the migration throughout the Americas occurred rapidly relative to the mtDNA mutation rate. HLA DRB1 alleles 1602 and 1402 were frequent among the Mapuches. These alleles also occur at high frequency among other Amerinds in North and South America, but not among Spanish, Chinese or African-American populations. The high frequency of these alleles throughout the Americas, and their specificity to the Americas, supports the hypothesis that Mapuches and other Amerind groups are closely related.(ABSTRACT TRUNCATED AT 250 WORDS)