Pollen coat protein gene families

Plant fertilisation is a highly specific process involving the interaction of a number of pollen coat protein families with the surface of the stigma. In the 29 June Science Jacob Mayfield and colleagues from the University of Chicago report the identification of clusters of genes that encode these pollen coat proteins in the brassica Arabadopsis thaliana (Science 2001, 292:2482-2485).

Mayfield et al. identified two distinct clusters of coat proteins; one cluster encoding six lipases and the second a group of six lipid-binding oleosin genes, including the pollination initiation gene GRP17. Following the identification of these gene clusters they decided to explore how these clusters were distributed in other 'ecotypes' — Arabadopsis strains from disparate geographical locations. They found that although there was variation within the genes themselves, the clusters were conserved across the ecotypes, suggesting a strong evolutionary pressure to maintain the clusters.

In addition they compared...