Estrildid finches are distributed throughout Africa, South Asia, Australia and neighbouring islands in the Indian and Pacific Oceans. Some specific phylogenetic and systematic debated questions have been clarified in the present study by mitochondrial cytochrome b DNA sequencing of 61 species of Estrildids and subsequent analyses of results by both Bayesian Inference and Maximum Likelihood methodologies. Our results support that Estrildids are a monophyletic group with polytomies that may have started evolving by Middle Miocene Epoch (about 16, 5 million years ago). This proposed timing is coincidental with the Fringillinae finches' radiation starting time and also with the biggest Hymalayan and Tibetan Plateau uplift, triggered by the Indian tectonic plate strongest collision; this established present day southern Asia monsoon regime and other drastic climatic changes, like a dryer weather in Tibetan Plateau and China deserts. The Estrildid finches form a monophyletic group which includes several polytomies and comprises African, Asian and Australian birds. The most ancient evolutive group comprises African (African silverbill), Asian (Indian silverbill) and Australian (diamond firetail); this suggests that the whole Estrildids radiation might have originated around India.More Estrildid species will be studied in order to further establish this group phylogeography. In addition, monophyletic radiations include species from different Continents. Finally, Ploceinae Genus Quelea finches is a group separate and basal from Estrildini and Viduini species in our dendrograms.
Uros population from the Titikaka Lake live in about 42 floating reed ('totora') islands in front of Puno City (Peru) at a 4000 m high altiplano. They present both an mtDNA and a human leucocyte antigen (HLA) profile different from the surrounding populations: mtDNA A2 haplogroup is common to Uros and Amazon forest lowland Amerindians. HLA genetic distances between populations have been calculated and neighbour-joining dendrograms and correspondence analyses were carried out. Approximately 15 006 HLA chromosomes from worldwide populations have been used for comparisons. Only eight HLA-A alleles have been found, three of them accounting for most of the frequencies. The same phenomenon is seen for HLA-B, HLA-DRB1 and HLA-DQB1 alleles: a few alleles (3, 4 and 3, respectively) are present in most individuals. The presence of HLA-B*4801 and HLA-DRB1*0901 alleles in a relatively high frequency (although not the most frequent alleles found) is a characteristic shared with Asians and some populations from the Andean altiplano. Three specific Uros haplotypes have been found among the most frequent ones: HLA-A*680102-B*3505-DRB1*0403-DQB1*0302; HLA-A*2402-B*1504-DRB1*1402-DQB1*0301; and HLA-A*2402-B*4801-DRB1*0403-DQB1*0302. The present study suggests that Uros may have been one of the first populations from the shores of the Titikaka Lake coming from the Amazonian forest, which might have given rise to other later differentiated ethnic group (i.e. Aymaras). Uros HLA profile is also useful to study genetic epidemiology of diseases linked to HLA and to construct a future transplant waiting list by adding up regional lists in order to get a bigger pool for transplanting with better HLA matching.
The classical three-waves theory of American peopling through Beringia was based on a mixed anthropological and linguistic methodology. The use of mtDNA, Y chromosome and other DNA markers offers different results according to the different markers and methodologies chosen by different authors. At present, the peopling of Americas remains uncertain, regarding: time of population, number of peopling waves and place of peopling entrance among other related issues. In the present review, we have gathered most available HLA data already obtained about First Native American populations, which raise some doubts about the classical three waves of American peopling hypothesis. In summary, our conclusions are: 1) North West Canadian Athabaskans have had gene flow with: a) close neighboring populations, b) Amerindians, c) Pacific Islanders including East Australians and d) Siberians; 2) Beringia was probably not the only entrance of people to America: Pacific Ocean boat trips may have contributed to the HLA genetic American profile (or the opposite could also be true); 3) Amerindians entrance to America may have been different to that of Athabaskans and Eskimos and Amerindians may have been in their lands long before Athabaskans and Eskimos because they present and altogether different set of HLA-DRB1 allele frequencies; 4) Amerindians show very few “particular alleles”, almost all are shared with other Amerindians, Athabaskans and Pacific Islanders, including East Australians and Siberians; 5) Our results do not support the three waves model of American peopling, but another model where the people entrance is not only Beringia, but also Pacific Coast. Reverse migration (America to Asia) is not discarded and different movements of people in either direction in different times are supported by the Athabaskan population admixture with Asian-Pacific population and with Amerindians, 6) HLA variability is more common than allele veriability in Amerindians. Finally, it is shown that gene genealogy analises should be completed with allele frequency analyses in population relatednes and migrations studies.
Birds are considered dinosaurs that passed the 65 million years ago bottleneck. Songbirds (Passeriformes) include about half extant bird species (about 5000) and are generally the most air-thriving bird species, concordantly with their small size. Mayor Histocompatibility complex (MHC) molecules stimulate immune responses against microbes and its class I molecules have seven conserved residues in all vertebrates from jawed-fishes, 300 million years ago, to humans, including chickens.All wild songbird species tested by us (n=18) and others (n= 2) differ in α1 domain residue 10 and α2 residue 96 from all other vertebrates. Amplification, cloning and sequencing were performed by standard methods. Sequences alignment were done by using PAUP and MEGA programs software. Crystallographic studies were performed by using mammal and bird MHC molecules from MPID database and other sources and showed that these changes did not significantly vary the MHC class I molecule stability in songbirds.Further α1 and α2 domain comparisons by simple Composition Distances and Bayesian Inference showed that songbirds overall MHC class I molecules are phylogenetically more separated from mammal than other birds molecules. In addition MHC class I introns from Passeriformes (songbirds) were found to be longer than humans, chicken introns being the shortest ones.These small mainly air-borne dinosaurs (Passeriformes) have undergone a different evolutive pathway, regarding to MHC, than all other tested vertebrates and more terrestrial birds. This may have been originated by an altogether different dinosaurs linage origin or to adaptation to more aerial than terrestrial environment or other unknown cause. In any case, the specific changes observed in this work for class I molecules in songbirds have reached a entropic, stable solution similar to that reached by other vertebrates.
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