What is interesting about genetic analysis is the way it has the potential to upset otherwise well-established classifications of animals. A good example is the Mammoth, Ice Age beasts well known to one and all.
Although they both roamed North America a millennia ago, accepted taxonomy had classified the woolly mammoth (Mammuthus primigenius) and Columbian mammoth (Mammuthus columbi) as two species. The smaller woolly mammoth was hypothecated to have immigrated from Eurasia, while the larger Columbian mammoth was considered native to North America.
Researchers, using a very limited "data set" (one well-preserved Columbian mammoth from Utah and one less well-preserved one from Wyoming), found that DNA analysis placed both on the same branch of the genetic "family tree" as a subgroup of woollies. Critics have justifiably noted that limited data, and are not embracing the new classification absent more DNA evidence. This is perfectly reasonable, especially given that to date the analysis has only assessed DNA from the mitochondria. Researchers have noted that mitrochondrial DNA and DNA from other cell nuclei do not always point to the same conclusion. More assessments will be forthcoming.
The report can be found at http://genomebiology.com/2011/12/5/R51.