The skeleton, with a dramatically elongated skull and an underdeveloped jaw and face, was uncovered in Chile's Atacama Desert in 2003, and mystified scientists when it was first found.
Examination of the skeleton's entire genome revealed that it was Chilean and female..
a highly detailed analysis — including X-rays, computed tomography (CT) scans and DNA sequencing — showed that it was a fetus (and that it was definitely human). Despite the skeleton's minuscule size, previous analysis cast doubt on whether it was a fetus because its "advanced bone age" more closely resembled that of a young child, particularly in the structure of the skeleton's skull, with sutures that were already fused.
...scientists found .. mutations in seven of the fetus's genes: COL1A1, COL2A1, KMT2D, FLNB, ATR, TRIP11 and PCNT. Mutations in these genes are known to play roles in premature joint fusion, abnormalities in rib development, malformed skulls, and diseases that inhibit the development of bone and cartilage, according to the study.
Taken together, the mutations expressed by these genes would explain all of the fetus's skeletal abnormalities, the scientists concluded. However, finding so many mutations that specifically affect skeletal development is unusual; in fact, it's never been reported before, and it is unknown what triggered this cascade of mutations, study lead author Garry Nolan, a professor of microbiology and immunology at Stanford University, told Live Science in an email.
"The era of single gene/single disease is just about over — it's now time to look at the more subtle effects when genes interact," Nolan wrote. "In isolation, a gene might have no effect ... but combined with other genes, the outcomes can be dramatic." "These studies show that certain gene mutations can 'vote' towards a given body plan or disease," Nolan said.
The findings were published online today (March 22) in the journal Genome Research.