PRJNA284903
Characterization of the genome and transcriptome of the blue tit Cyanistes caeruleus: polymorphisms, sex-biased expression and selection signals
The investigation of genomic variation in populations helps in understanding recent adaptive processes of ecologically relevant trait variation. The blue tit – a long time ecological model – has been used to investigate fitness consequences of different behavioural and mating strategies. However, very little is known about the underlying genetic changes due to natural and sexual selection in the genome of the bird. As a step to bridge this gap we assembled the first draft genome of a single blue tit, mapped the transcriptome of five females and five males on this reference and identified genomic variants.In the gonads we found a similar proportion of sex-limited genes within the high number of male- and female-biased genes, respectively, whereas in the brain most female-biased genes were also female-limited and most male-biased genes were located on the Z-chromosome with expression in both sexes. This indicates incomplete dosage compensation for the male-biased genes, but a different qualitative control mechanism for the female-biased genes. We called more than 500,000 SNPs from the RNA-seq data with a high specificity and sensitivity in comparison to the DNA-seq calling (both > 80%). After utilizing different information of these polymorphisms we identified the strongest selection signals in the genome.We list candidate genes which can be used for further sequencing and detailed selection studies, including genes potentially related to meiotic drive evolution.