Molecular mechanisms of sperm evolution in passerine birds

A major challenge in evolutionary biology is to explain the diversification of phenotypes and how they are encoded in the genome. One phenotype that has captured the interest of many biologists is the sperm cell. Sperm cells are one of the most varied cell types in the animal kingdom which is surprising given their universal function of ovum fertilization. In birds, there is considerable variation in both overall sperm cell length and the relative size and shape of its components, even among closely related taxa. We have been examining several avian species with diverse sperm morphology in order to identify the molecular mechanisms responsible for these phenotypic differences. In the model species, zebra finch, there is an inversion on the Z chromosome that, when heterozygous, produces a longer midpiece than either homozygous inversion type. In the Eurasian bullfinch, sperm are very short with a small midpiece and small acrosome and do not have a helical head as in other passerine birds. We are using these two phenotypes and other species with variation in length and midpiece to understand how these phenotypes may have evolved. I will present results on the impact of the Z chromosome inversion on gene expression and some preliminary results from the other taxa. 

I am currently a Senior Lecturer in marine biodiversity at the University of Gothenburg and have an affiliation at the Natural History Museum at the University of Oslo. I am trained in population genetics, but since my PhD I have become more interested in the functional aspects of population and species divergence. In the most general terms, I am interested in understanding the genetic changes that result in phenotypic differences. I have been using whole-genome approaches: genome sequencing, transcriptomics and proteomics, to identify genes and pathways involved in adaptation to novel environments as well as to examine the molecular bases of sex-specific differences and sperm evolution. I work a variety of marine taxa (fish and marine invertebrates) as well as birds. 

[Hosts: Rui Faria and Ricardo Lopes, Evolutionary Genetics and Genomics - EVOLGEN]