Variabilidade e história evolutiva do gene HLA-E
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Data
2013-01-31
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Universidade Federal de Goiás
Resumo
The HLA-E locus is a Human Major Histocompatibility Complex (MHC) gene
associated with immune-modulation and suppression of the immune response by the
interaction with specific NK and T cell receptors. The HLA-E gene is considered the
most conserved locus in the human HLA; however, this low variability might be a
consequence of the scarce number of studies focusing this subject. In this mastering
thesis we assessed the HLA-E coding and 3’ untranslated region variability in a
group of individuals from Brazil and the results were evaluated together with data
from the 1000Genomes Consortium. Altogether, only 28 variation sites were found in
approximately 2724 bp evaluated. These variation sites were arranged into 33
haplotypes, most of them (98.2%) encoding one of the two HLA-E molecules found
worldwide, i.e., the molecules associated with the allele groups E*01:01 and E*01:03.
Interestingly, 85% of all haplotypes were represented by only three different
sequences, each of them associated with one of the main known HLA-E coding
alleles, E*01:01:01, E*01:03:01 and E*01:03:02, all of them found worldwide. This
phenomenon, together with the comparisons with other primate sequences, reveals
that these two main allele groups (and molecules) arose early before human
speciation, and indicates that E*01:03:01 might be the oldest allele. In addition, the
low nucleotide diversity found for the HLA-E coding and 3’UTR in worldwide
populations suggests that the HLA-E gene is in fact a conserved gene, which might
be a consequence of its key role in the modulation of the immune system.
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FELÍCIO, Leandro Prado. Variabilidade e história evolutiva do gene HLA-E. 2013. 77 f. Dissertação (Mestrado em Biologia) - Universidade Federal de Goiás, Goiânia, 2013.