A Y-chromosome map between the gibbon Nomascus leucogenys and Humans: Evolutionary inferences and biomedical applications

• Autor(a) principal: Costa, Liliana Sofia Meireles da
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10348/8749
• topic: gibbon; Y chromosome; satellite III DNA; comparative mapping

Gibbons, also called as the lesser apes, were the first to branch off from the other hominids at approximately 16–20 million years ago, thus providing a unique perspective to study the evolution of human. These lesser apes are an example of fast rate of karyotype change. Nomascus leucogenys was the first gibbon species to have its genome sequenced; however, the sequenced individual was a female. Thus, still missing is information about the genomic sequence and structure of the Y chromosome of this species. Genomic information on the Y chromosomes of multiple species will allow novel insights into the evolution of Y chromosomes and their fundamental biological functions. The Y chromosome generally is enriched in repetitive sequences in addition to single copy sequences. Also, a considerable part of the eukaryotic genomes are repetitive sequences, which lately have gained more attention due to the discovery of their functions – satellite III DNA, for example, is involved in the pathway of the cellular stress response. In this thesis, the aimed was to construct a comparative map for the Y chromosome of Nomascus leucogenys. Initially, human BAC clones were used as probes to perform the fluorescence in situ hybridization (FISH) on human and gibbon metaphase chromosomes and on extended chromatin fibres. Next, the satellite III DNA was isolated, characterized and mapped on gibbon and human chromosomes, through cloning, and FISH, as well as bioinformatic analysis was made to accomplish an in silico analysis of the isolated sequences. The gibbon Y chromosome appeared to be conserved in terms of sequence (gene) content or synteny, since it was possible to map 19 human probes that contain in total 15 genes. However, structurally, this chromosome seems to be entirely rearranged in relative to the human Y chromosome. In contrast, the satellite III DNA sequences seems to be conserved with respect to its location on the chromosome regions. But at the DNA sequence level, the in silico analysis revealed a great variability, in both human and gibbon genomes. A deeper study of the Y chromosome is relevant, including its sequencing, since this chromosome comprised genes that play important roles in the masculinization, and in other tissues/functions throughout the body.