| Description |
Homologous chromosomes of somatic tissue pair together in Drosophila. One current model proposes that somatic pairing starts in an undirected manner; when sites on the chromosome, called "buttons", come into contact and pair. Then, after this initial pairing, the rest of the chromosome then synapses together with its homologous partner. However, there is a reduction in homologous chromosome pairing of larval polytene tissue of interspecific Drosophila hybrids. Within these less-paired sets of chromosomes, there are non-random points where pairing remains more consistent. We used Hi-C chromosome conformation capture and Illumina sequencing in an attempt to identify any relation between somatic chromosome pairing and relative replication rates in interspecific hybrids. Along with this change in somatic pairing, interspecific hybrids also exhibit female infertility and male death. Hybrids heterozygous for knockout mutations of Lhr and Hmr partially recover from these effects. We tested hybrids with mutations to Lhr and Hmr to determine if the reduction of pairing was related to these hybrid effects. We saw that within species hybrids relative pairing proportion and relative Illumina coverage followed similar trends while interspecific hybrids showed regions where relative pairing proportion increased when relative Illumina coverage decreased. We observed the inverse, relative pairing proportion decreased when relative Illumina coverage increased, to a lesser degree. Furthermore, interspecific hybrids that are heterozygous for Lhr and Hmr knockouts showed little difference from interspecific hybrids without any knockouts. This indicates that polytene somatic chromosome pairing is not directly related to hybrid female infertility or male death. |
