Using L1 tagged with a fluorescent marker, the group observed higher numbers of fluorescent iPSCs from non-human primates compared with humans. In separate experiments, they produced iPSCs with too much or too little APOBEC3B and PIWIL2, finding——as expected——that an excess of the two proteins dampened the mobility and reduced the appearance of newly inserted DNA in the non-human primate cells.
These results suggested that L1 elements insert themselves less often throughout our genomes. Indeed, looking at genomes of humans and chimpanzees that had already been sequenced, the researchers found that the primates had more copies of L1 sequences than did humans.
The question that remains is, what would be the impact of differences in L1 regulation? "It could mean that we have gone, as humans, through one or more bottlenecks in evolution, that decrease the variability present in our genome," says Marchetto, though the hypothesis is admittedly hard to prove. It is known, however, that humans' genomes are less variable than chimpanzees'.
Read more at: http://phys.org/news/2013-10-pluripotent-stem-cells-reveal-differences.html#jCp
These results suggested that L1 elements insert themselves less often throughout our genomes. Indeed, looking at genomes of humans and chimpanzees that had already been sequenced, the researchers found that the primates had more copies of L1 sequences than did humans.
The question that remains is, what would be the impact of differences in L1 regulation? "It could mean that we have gone, as humans, through one or more bottlenecks in evolution, that decrease the variability present in our genome," says Marchetto, though the hypothesis is admittedly hard to prove. It is known, however, that humans' genomes are less variable than chimpanzees'.
Read more at: http://phys.org/news/2013-10-pluripotent-stem-cells-reveal-differences.html#jCp
