Torosin, N. | bioRxiv Science

bioRxiv2023

Long-read genome assemblies for the study of chromosome expansion: Drosophila kikkawai Drosophila takahashii, Drosophila bipectinata, and Drosophila ananassae

Flow cytometry estimates of genome sizes among species of Drosophila show a 3-fold variation, ranging from [~]127 Mb in Drosophila mercatorum to [~]400 Mb in Drosophila cyrtoloma. However, the assembled portion of the Muller F Element (orthologous to the fourth chromosome in Drosophila melanogaster) shows a nearly 14-fold variation in size, ranging from [~]1.3 Mb to > 18 Mb. Here, we present chromosome-level long read genome assemblies for four Drosophila species with expanded F Elements ranging in size from 2.3 Mb to 20.5 Mb. Each Muller Element is present as a single scaffold in each assembly. These assemblies will enable new insights into the evolutionary causes and consequences of chromosome size expansion.

genomics↗

bioRxiv2019

Positively selected variants in functionally important regions of TLR7 in Alouatta guariba clamitans with yellow fever virus exposure in Northern Argentina

1In 2007-2009, a ma jor yellow fever virus (YFV) outbreak in Northern Argentina decimated the local howler monkey (Alouatta) population. We explored the relationship between Toll-like receptor (TLR) 7 and TLR8 gene variation and YFV susceptibility using samples from Alouatta individuals alive before the YFV outbreak, individuals that died during the outbreak, and individuals that survived the outbreak and are alive today. We measured genetic divergence between Alouatta YFV exposure groups and evaluated Alouatta-specific substitutions for functional consequences. We did not find different allele frequencies in the post-YFV exposure Alouatta group compared to the pre-exposure group. However, we identified three nonsynonymous variants in TLR7 in A. guariba clamitans. Two of these substitutions are under positive selection in functionally important regions of the gene. These unique coding differences in A. guariba clamitans may affect YFV resistance, but more work is necessary to fully explore this hypothesis.

evolutionary biology↗