by Vera Pertsovskaya
A common phenomenon seen throughout animals is sexual dimorphism–the condition that describes the phenotypic difference between males and females of the same species. A major force behind the evolution of this sexual dimorphism is gene duplication–a critical process in the creation of genes with novel functions and consequently the evolution of biological diversity. Gene members of the same duplicate family can have differing expression patterns in males than in females. One area in which gene duplication has had a profound impact on sex differences is the generation of testis-specific genes that are required for spermatogenesis to work. The transcriptomes of Drosophila and several vertebrates have shown that testis-specific genes are the most abundant class of tissue-specific genes. One prominent example in Drosophila is the Transcription initiation factor TFIID subunit 5 (TAF 5) gene. This gene is an essential component of the basal transcription machinery—which controls transcription in all cells and has a duplicate in the genome. This duplicate copy is expressed only in the testis and is essential for the progression of the meiotic cell cycle in order for the spermatogenesis process to occur. Our goal in this study was to investigate the diversification of TAF 5 genes within stalk-eyed flies (Diopsidae); preliminary studies have identified several testis specific copies in one species of stalk eyed flies. Flies in this family are known for their elongation of the head into long stalks–a condition known as hypercephaly–and have become a model for studying sexual selection. (American Museum of Natural History, Sackler Institute for Comparative Genomics. Mentor: Richard Baker).
Journal of Undergraduate Research at Hunter College 