Priya Srikanth Finishing2

The small fourth chromosome of Drosophila melanogaster, also known as the dot chromosome, is unlike the other three chromosomes of Drosophila in that it contains largely heterochromatic sequence. The 1.2 Mb arm of the dot chromosome has normal gene density, but a higher frequency of repetitive sequences compared to the euchromatic arms of chromosomes 13. The many genes packaged in the dot chromosome’s heterochromatic regions are expressed more strongly than genes in the heterochromatic regions of other chromosomes. This unusual chromosome provides an opportunity to study differences in euchromatin and heterochromatin coding and formation. To investigate the effects of sequence organization on formation of heterochromatic and euchromatic domains, Bio 4342 has used comparative genomics, looking at dot chromosome sequences from D. melanogaster and D. virilis. 2007 marks the start of analysis of a new dot chromosome – that of D. mojavensis. My project focuses on finishing clone 430-O17 from this chromosome.