Zoology Department Seminar: Evolution of germ-line restricted and unrestricted genomes in diptera

Speaker: Kamil Jaron, Sanger Institute

Abstract: Flies show a remarkable diversity of ways genomes are organised. From rapidly inverting genomes of some of the Drosophilidae species, to remarkably stable genomes of phantom craneflies. We have analysed a dataset of 340 chromosomal level assemblies to map this diversity and characterise the mode of evolutionary change in genomes of Diptera. Contrary to common believe, the notorious Muller elements do not represent the ancestral linkage groups, they are a derived karyotype that evolved in the common ancestor of Schizophora and hoverflies. Using the ancestral linkage group reconstruction as the framework, we characterised sex chromosome evolution too. The ancestral dipteran X chromosome is a gene-poor chromosome that varies in size many fold across dipteran species, showing signatures more typical for B-chromosomes or Y chromosomes. This is at a sharp contrast to germ-line restricted chromosomes found in dark-winged fungus gnats. We have sequenced pool of testes of three species and reconstructed for the first time germ-line restricted chromosomes on chromosomal level. The chromosomes are found in haploid state in male germline and were thought to be parasitic and likely non-recombining. Despite that, we showed they are depleted of repeats and show thousands of gene models. This talk will focus on covering the diversity of dipteran genomes and try to phrase well how is that contradicting our expectations.

Our Departmental Seminars run weekly on Thursdays during term time. They cover recent research on a wide variety of topics from evolutionary genetics through behavioural ecology to ecology and natural history.  

Everyone in Zoology is invited, and Part II undergraduate zoologists are particularly encouraged to attend.  Please click here for a list of all of this term's seminars.