Project Details
Projekt
Dynamics of chromosome evolution in termites: Inbreeding, novel chromosomal translocations and sociality
Subject Area
Evolution, Anthropology
General Genetics and Functional Genome Biology
General Genetics and Functional Genome Biology
Term
since 2022
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 503256468
Continuing advances in the accuracy, yield and cost of long- and short-read sequencing have revolutionized the scope of genomic research in non-model organisms. We harness this newly available opportunity to gain insights into the evolutionary causes and consequences of chromosome ring formation in termites. Rings or chains of bound multiple chromosomes have been observed during male meiosis in many termite lineages, and the widespread occurrence of this trait suggests an important association between chromosomal modification and evolution in this group. The formation of chromosome rings could have repercussions over different evolutionary timescales, and we focus on two contrasting levels in our proposal. Firstly, we investigate the association between chromosome ring formation and the evolution of chromosomes across the transition to termite eusociality. Here, we will ask whether chromosomal rings are connected to large-scale translocation events, and whether such rearrangements have been instrumental in the formation of new chromosomes, including sex chromosomes, in termites. Secondly, we explore whether chromosomal ring formation has contributed to termite evolution over more recent timescales. We use European species of Reticulitermes as a study system to test the hypothesis that ring chromosome formation represents an evolutionary response to elevated levels of inbreeding. Inbreeding is found in many extant termite lineages and is thought to have played an important role during the origin of termites. In addition to an association with inbreeding, we ask to what extent chromosomal ring formation has shaped the genomic histories of termite populations and recently diverged species. Specifically, we explore how chromosome rings (and associated structural variants) may have acted as genomic regions of divergence, by altering patterns of genetic variation between populations and closely related species through their suppressive effects on recombination. Here, we will derive population statistics, and conduct principle component and admixture analyses on genome-wide nucleotide variants from re-sequenced genomes of individual termites from populations sourced throughout the European range. We will derive measures of within- and between population genetic diversity and examine the extent to which non-neutral loci differentiating populations may be correlated with chromosome-ring formations and associated structural variants. Our overall goal is to sequence and analyze four high-quality termite genomes and carry out whole-genome re-sequencing of 200 individuals from four European Reticulitermes termites. Together with existing data, this will allow us to test hypotheses linking ring-chromosome formation with i) patterns of inbreeding, ii) the origin of (sex) chromosomes, iii) the emergence of structural variants such as translocations, and iv) patterns of genetic differentiation and adaptation within and between species.
DFG Programme
Priority Programmes
