Using data from the 1000 human genome project, these researchers are suggesting that recent mutations are more involved in disease protection or susceptibility rather than ancient mutations. They attempt to present a unified theory of genetic disease that encompasses both common and rare Mendelian, multiple allele, SNP, and copy number variation mutations. Especially important in their observations is that many diseases are caused by rare alleles, signifying that mutations in the last two generations have a huge impact on disease.
Also, this is a news article that discribes the research as well. http://www.sciencedaily.com/releases/2011/09/110929122751.htm