The diverse origins of New Zealand house mice

Abstract

Molecular markers and morphological characters can help infer the colonization history of organisms. A combination of mitochondrial (mt)d-loop DNA sequences, nuclear DNA data, external measurements and skull characteristics shows that house mice (Mus musculus) in New Zealand and its outlying islands are descended from very diverse sources. The predominant genome isMus musculus domesticus(from western Europe), butMus musculus musculus(from central Europe) andMus musculus castaneus(from southern Asia) are also represented genetically. These subspecies have hybridized to produce combinations ofmusculusanddomesticusnuclear DNA coupled withdomesticusmtDNA, andcastaneusormusculusmtDNA withdomesticusnuclear DNA. The majority of the mice withdomesticusmtDNA that we sampled hadd-loop sequences identical to two haplotypes common in Britain. This is consistent with long-term British–New Zealand cultural linkages. The origins of thecastaneusmtDNA sequences widespread in New Zealand are less easy to identify.