A Nice, Long, Sequence For The Mummichog DNA

I met with Kris yesterday afternoon for an update on his mummichog population genetics project. He now has phylogenetic trees based on a sequence of 775 base pairs of the cyt-b mtDNA gene, a good stretch of the total 1160 base pairs. Analysis of this longer stretch of gene confirms and clarifies what we'd seen with shorter stretches: that the New England populations have very little genetic difference between them, and that the New England populations are measurably different from populations from the Delmarva peninsula south to Georgia. The latter point is hardly new in of itself, but our data strongly suggest that these New England fish are descended from a very small founding population that colonized the New England coast after the glaciers retreated ~13,000 years ago. One way to quantify this separation is by percent differentiation: the New England and southern populations are about 1.4% divergent. By way of comparison to another Fundulus species, the longnose killifish, F. similis, which we're using as an outgroup is about 7.5% divergent from the mummichog populations.

I just realized we're due for another trip to Limestone Creek to collect scarlet shiners. The pair I have in a lab aquarium are beginning to peak in terms of breeding coloration and apparent egg production. Those pituitary hormones are powerful chemicals.