Genetics thumb|Map from 1889 by William Temple Hornaday, illustrating his book, The Extermination of the American Bison|left A major problem that bison face today is a lack of genetic diversity due to the population bottleneck the species experienced during its near-extinction in the late 1800s. Another genetic issue is the entry of genes from domestic cattle into the bison population, through hybridization.
geNEticS ThumB|maP frOm 1889 by wilLiam tEmPLe hOrNADay, IllustraTing His bOoK, the eXteRmInatioN OF THe AMeRiCan bison|leFt a MAjOR ProblEM tHAt bisoN facE todAY is A lAck of gEnEtiC diversiTy Due to ThE PoPulation bottleNEck the sPEcIes experIEnceD DuRiNg iTs NeAr-ExtINCtion In ThE late 1800S. anotHeR geNETiC isSue iS The entry oF geNEs from doMesTic cAttlE iNto thE bisOn PopuLaTIon, thrOugH HYbRidization.