 A genetic study published in 2005 confirmed the subspecific status of the quagga . It showed that the quagga had little genetic diversity , and that it diverged from the other plains zebra subspecies only between 120 @,@ 000 and 290 @,@ 000 years ago , during the Pleistocene , and possibly the penultimate glacial maximum . Its distinct coat pattern perhaps evolved rapidly because of geographical isolation and / or adaptation to a drier environment . In addition , plains zebra subspecies tend to have less striping the further south they live , and the quagga was the most southern @-@ living of them all . Other large African ungulates diverged into separate species and subspecies during this period as well , probably because of the same climate shift . The simplified cladogram below is based on the 2005 analysis ( some taxa shared haplotypes and could therefore not be differentiated ) : 
