A study of the karyotype of a population of banded killifish (Fundulus diaphanus) from the Hudson Rive

Abstract

Studies were carried out to find appropriate techniques for securing a suitable karyotype from a population of Fundulus diaphanus in the Hudson River and to compare it with a published karyotype of a population of the same species from the New Haven, Connecticut area. A modification of the basic method of Denton & Howell proved to be a simple, effective and inexpensive approach for acquiring numerous and distinct chromosomal spreads for detailed karyotype analyses. The two karyotypes were identical in modal number, arm number and number of submetacentrics; however, they differed in numbers of acrocentrics and secondary constrictions. These differences may indicate incipient chromosomal evolution with the two distinct environments acting as selective agents. Preliminary work was carried out with banding techniques; the modified Denton & Howell method with banding appears to be an effective and promising direction for fish cytogenetics.