Recently, Y chromosome markers have begun to be used to study Native American origins. Available data have been interpreted as indicating that the colonizers of the New World carried a single founder haplotype. However, these early studies have been based on a few, mostly complex polymorphisms of insufficient resolution to determine whether observed diversity stems from admixture or diversity among the colonizers. Because the interpretation of Y chromosomal variation in the New World depends on founding diversity, it is important to develop marker systems with finer resolution. Here we evaluate the hypothesis of a single-founder Y haplotype for Amerinds by using 11 Y-specific markers in five Colombian Amerind populations. Two of these markers (DYS271, DYS287) are reliable indicators of admixture and detected three non-Amerind chromosomes in our sample. Two other markers (DYS199, M19) are single-nucleotide polymorphisms mostly restricted to Native Americans. The relatedness of chromosomes defined by these two markers was evaluated by constructing haplotypes with seven microsatellite loci (DYS388 to 394). The microsatellite backgrounds found on the two haplogroups defined by marker DYS199 demonstrate the existence of at least two Amerind founder haplotypes, one of them (carrying allele DYS199 T) largely restricted to Native Americans. The estimated age and distribution of these haplogroups places them among the founders of the New World.

Sediments and mussel specimens of Mytilus chilensis were analyzed for organic pollutant fingerprints and heavy metals in the Corral Bay area of Valdivia, South Central Chile during the period [2003][2004]. GC-MS analysis show hydrocarbon fingerprints corresponding mainly to mixed inputs of aliphatic hydrocarbons of the TPH-diesel fraction and biogenic hydrocarbons, indicating low to medium contamination by petroleum hydrocarbons with high biodegradation of petroleum in sediments at Las Coloradas, La Escuela and Corral Bay (C 17 /Pri < 1 and C 18 /Phy < 1). Mussel TPH fingerprints show weathered hydrocarbons resulting in a zone of increased concentration of cyclic respect to acyclic aliphatic components (UCM), indicating the presence of petroleum hydrocarbons. No temporal variation the in concentration of TPH-diesel found in sediments as well as mussels were observed except for samples collected during January 2004. TPH concentration levels in the sediments varied from 0.4 µgg -1 to 33.8 µgg -1 d.w. whereas in mussels varied between 61 µg g -1 and 287 µgg -1 d.w. Heavy metals were also analyzed by atomic absorption spectrometry and low concentration as well as no seasonal variations of concentration were found in mussels at each sampling point and a relatively even distribution of metals among stations was observed. Maximum concentrations in all sampling points of sediments were found for Fe (24128-43791 µgg -1 ) and Mn (181-388 µgg -1 ) while the minimum concentration was found for Pb (nd-12 µgg). According to the Sediment Quality Guidelines (SQGs-NOAA), the concentration levels of Cu and As in all sediment sampling points are above the "Effects Range-Low" (ERL), indicating that there may be a probable toxicity effect over the biota and attention must be paid on a moderate range of priority.