Meeting Abstract
Animals that use an evolutionarily derived parental care strategy, rather than a strategy that is ancestral to its group, may provide unique insight into the genetic architecture of parental care. Roughly 1% of bird species are brood parasitic, which is an evolutionary derived strategy in which males and females display no parental care whatsoever. We explore this alternative parental strategy by examining the genomic basis for brood parasitism using brain region-specific transcriptome comparisons. Using comparative transcriptomic approaches, we identified gene expression patterns specifically within the preoptic area (POA), a brain region that plays a critical role in the regulation of maternal care. We compared POA transcript patterns in parasitic brown-headed (Molothrus ater) and bronzed cowbirds (M. aeneus) in relation to juvenile and adult red-winged blackbirds (Agelaius phoeniceus), a closely related non-parasitic species. We evaluated three alternative explanations for the evolution of brood parasitism: reduced expression of parental care-related genes in the POA, increased expression of genes inhibiting parental care, and retention of juvenile-like (neotenic) gene expression. We did not find evidence for large scale gene downregulation in brood parasites. Expression patterns did reflect substantial evidence for neotenic POA gene expression in parasitic birds. Differentially expressed genes with previously established roles in parental care were identified as well as genes that may inhibit parental care. These results provide a foundation to further examine whether the neural- and genetic-basis underlying brood parasitism is conserved across other parasitic species.
