A study on the functions of new Y-linked genes through expression analysis of Drosophila\'s spermatogenesis

Author(s)

Carolina de Athayde Mendonça

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2020-12-10

Examining board members

Maria Dulcetti Vibranovski; Rodrigo Cogni; Leonardo Barbosa Koerich

• Advisor: Maria Dulcetti Vibranovski

Abstract

The study of Drosophila melanogaster Y chromosome has always been slow even in the genomic era mainly because of its heterochromatic nature. Ingenious methods lead to the mapping of six fertility factors and the identification of 12 single-copy genes. These genes were originated from duplications of autosomes. The comparison of the expression profile of a gene that is Y-linked in one species and autosomic in a second species may shed light on the evolution of the expression profiles of Y-linked genes. To test different evolutionary hypotheses, stage-specific (mitosis, meiosis and post-meiosis) spermatogenesis RNAseq were conducted for D. melanogaster, D. willistoni and D. mojavensis. Differential expression analysis revealed that the increase in expression from mitosis to meiosis is commonly found in Y-linked genes and in its autossomic orthologs. This suggests that the increase in meiosis is an ancestral character that was selected among genes duplicated to the Y. On the other hand, the maintenance/increase in post-meiosis seems to be more common among Y-linked genes in relation to their autossomic ancestors. The Y genomic context may favour the expression in later phases of spermatogenesis and some possible mechanisms are the formation of lampbrush-like loops> and epigenetic marks. Thus, natural selection and genomic context are relevant on determining the expression profiles of Y-linked genes. (AU)

• FAPESP's process: 17/14923-4 - A study on the functions of new Y-linked genes through expression analysis of Drosophila's spermatogenesis
• Grantee: Carolina de Athayde Mendonça
• Support Opportunities: Scholarships in Brazil - Master