Red wolf DNA is still preserved in some coyote species

The Science News Magazine provided an article about a discovery related to red coated wolves. The physical appearance of the red coated coyotes in Texas brought up an interesting debate of how genes from extinct species of red wolves might still be preserved. Ron Wooten, a wildlife biologist believed that their appearance was strange. Their DNA was tested and the hypotheses were considerable true as the evidence showed that the Texas coyotes could be descendants of red wolves. It is necessary to take into consideration that these species were declared extinct from the wild almost forty years ago. This was not enough evidence to support their experiment. There is only a small population of red wolves in North Carolina which belong to a captive breeding. But this did not make a difference in the research because these wolves do not have any contact with other canids at all. Texas coyotes were to be tested and even though pictures showed  reddish coats and their heads being broader than regular coyotes, once again, this was not enough evidence. Tissue samples were obtained from coyotes that haven been killed in roads by cars driving by. Such samples were tested and at least two of the samples carried red wolf DNA. Another biologist, Elizabeth Heppenheimer from Princeton University was also very surprised that these were still present in these species.

I think this was a very interesting article because I did not think that species that are mostly extinct will leave their DNA behind, and this would be preserved for a few decades in other species. But, if we analyze the situation, if the DNA from humans can be passed through different generations why cannot animals go through the same process? 

A pair of 7 weeks old red wolf pups at a Museum of  Life and Science in North Carolina