 Introduction of these quagga @-@ like zebras could be part of a comprehensive restoration program including such ongoing efforts as eradication of non @-@ native trees . Quaggas , wildebeest , and ostriches , which occurred together during historical times in a mutually beneficial association , could be kept together in areas where the indigenous vegetation has to be maintained by grazing . In early 2006 , the third and fourth generation animals produced by the project were considered looking much like the depictions and preserved specimens of the quagga . This type of selective breeding is called breeding back . The practice is controversial , since the resulting zebras will resemble the quaggas only in external appearance , but will be genetically different . The technology to use recovered DNA for cloning does not yet exist . 
