GENETICS, EVOLUTION, AND PHYLOGEOGRAPHY OF MOOSE

Abstract

Early studies of genetic variation in moose (Alces alces) indicated little variation. Recent studies have indicated higher levels of variation in nuclear markers; nonetheless, genetic heterogeneity of moose is relatively low compared with other mammals. Similarly, variation in mitochondrial DNA of moose is limited worldwide, indicating low historic effective population size and a common ancestry for moose within the last 60,000 years. That ancestor most likely lived in central Asia. Moose likely exhibit low levels of heterogeneity because of population bottlenecks in the late Pleistocene caused by latitudinal shifts in habitat from recurrent climate reversals. A northward movement of boreal forest associated with the end of the last ice age facilitated the northward advance of Asian populations and colonization of the New World, which occurred as a single entry by relatively few moose immediately prior to the last flooding of the Bering land bridge. Despite suffering serial population bottlenecks historically, moose have exhibited a notable ability to adapt to a changing environment, indicating that limited neutral genetic variation may not indicate limited adaptive genetic variation. We conclude that morphological variation among moose worldwide occurred within a few thousand years and indicates that moose underwent episodes of rapid and occasionally convergent evolution. Genetic change in moose populations over very short time scales (tens or hundreds of years) is possible under harvest management regimes and those changes may not be beneficial to moose in the long term. Modeling exercises have demonstrated that harvest strategies can have negative consequences on neutral genetic variation as well as alleles underpinning fitness traits. Biologists should consider such outcomes when evaluating management options.