 The quagga was the first extinct animal to have its DNA analysed , and this 1984 study launched the field of ancient DNA analysis . It confirmed that the quagga was more closely related to zebras than to horses , with the quagga and mountain zebra ( Equus zebra ) sharing an ancestor 3 – 4 million years ago . An immunological study published the following year found the quagga to be closest to the plains zebra . A 1987 study suggested that the mtDNA of the quagga diverged at a range of roughly 2 % per million years , similar to other mammal species , and again confirmed the close relation to the plains zebra . 
