Gene flow and hybridization following introduction of Mus domesticus into an established population

Seventy-seven house mice (Mus domesticus) from Eday, Orkney were released into a long-established population on the Isle of May (56o 12'N) in 1982. Introduced allozymes, mt and Y-chromosome DNA, and Robertsonian chromosomes spread rapidly, reaching approximate stability c. 3 years later at frequencies different to those in both parental populations. The hybrid population was morphometrically intermediate between the two parents. This is a preliminary summary only; full details will be published elsewhere.