Mechanisms of differential prenatal maternal investment in birds

In birds, egg size is known to have wide-reaching effects on chick phenotype, but little is understood about the mechanisms that lie behind differential investment in egg production. Egg size is strongly influenced by yolk size and faster growth of follicles in the ovary is correlated with larger yolks and eggs. In particular, the expression of the VTG/VLDL-R gene in the follicles has been linked to yolk size and egg size. Follicles are also the source of reproductive hormones and so the regulation of other genes in this tissue may also be important in altering egg size. To further investigate this, we have created repeated selection lines for egg size in Japanese quail (Coturnix japonica). We use RNA-seq to help identify differences in gene expression patterns between females that differ in reproductive phenotype