My lab is interested in how marine organisms become reproductively isolated during speciation.  One primary focus is gamete recognition in sea urchins and mussels.  We found a strong link between adaptive sperm protein evolution and fertilization barriers between recently formed species of tropical urchins.  We are now using experiments in laboratory flumes to see how sexual selection on sperm-egg recognition proteins is influenced by conditions of water flow and gamete densities around spawning green urchins.

Blue mussels offer an opportunity not available in sea urchins, and that is to study gamete recognition between species in which reproductive barriers are incipient, and hybridization occurs at high frequencies in natural populations.  In collaboration with colleagues in Maine, we are using in vitro fertilizations, molecular markers, and studies of sperm lysin proteins and their coding DNAs to study evolution of gamete incompatibility within the Gulf of Maine hybrid zone.

Mating preferences and color pattern diversity are thought to evolve rapidly in the famous cichlid fish flocks, but this pattern has remained unstudied in the most diverse vertebrate group—coral reef fishes.  Our lab has studied the recent radiation of strong assortative mating and vivid color pattern differences in the hamlets, a species flock of Caribbean coral reef fishes showing extraordinary genetic similarity.

We are also developing programs in conservation and fisheries genetics.  Ongoing work includes assessment of species status in endemic darters, genetic identification and endemic status of threatened freshwater mussels, studies of connectivity between Caribbean populations of mutton snapper, and studies of mixing between black sea bass stocks north and south of Cape Hatteras.

Click here to view my laboratory poster (pdf).

Barreto, F.S. and M.A. McCartney (2008).  Extraordinary AFLP fingerprint similarity despite strong assortative mating between reef fish color morphospecies.  Evolution 62:226–233.

Slaughter, C., McCartney, M. A. and P. O. Yund (2008). A comparison of gamete compatibility between two blue mussel species in sympatry and in allopatry.  Biological Bulletin 214: 57–66.

Zigler, K. S., M. A. McCartney , D. R. Levitan, and H. A. Lessios (2005)  Sea urchin bindin divergence predicts gamete compatibility.  Evolution 59: 2399-2404.

McCartney, M. A. and Lessios, H. A. (2004) Adaptive evolution of sperm bindin tracks egg incompatibility in neotropical sea urchins of the genus Echinometra.  Molecular Biology and Evolution 21:732-745.