Early human skull reveals signs of inbreeding
Washington: Skull pieces of an early human buried for 100,000 years at Xujiayao in the Nihewan Basin of northern China exhibit a now-rare congenital deformation that indicates inbreeding might well have been common among our ancestors.
The skull, known as Xujiayao 11, has an unusual perforation through the top of the brain case-an enlarged parietal foramen (EPF) or "hole in the skull"-that is consistent with modern humans diagnosed with a rare genetic mutation in the homeobox genes ALX4 on chromosome 11 and MSX2 on chromosome 5.
These specific genetic mutations interfere with bone formation and prevent the closure of small holes in the back of the prenatal braincase, a process that is normally completed within the first five months of fetal development. It occurs in about one out of every 25,000 modern human births.
Although this genetic abnormality is sometimes associated with cognitive deficits, the older adult age of Xujiayao 11 suggests that any such deficits in this individual were minor.
Traces of genetic abnormalities, such as EPF, are seen unusually often in the skulls of Pleistocene humans, from early Homo erectus to the end of the Paleolithic.
"The probability of finding one of these abnormalities in the small available sample of human fossils is very low, and the cumulative probability of finding so many is exceedingly small," study co-author Erik Trinkaus, the Mary Tileston Hemenway Professor of Anthropology in Arts and Sciences at Washington University in St. Louis said.
"The presence of the Xujiayao and other Pleistocene human abnormalities therefore suggests unusual population dynamics, most likely from high levels of inbreeding and local population instability," he added.
More from India
More from World
More from Sports
More from Entertaiment
- UP: Jammu-bound Muri Express derails in Kaushambi
- Five unmanned parachute-like objects spotted over Mumbai airport
- Aapke Sitare: Astro prediction for May 24, 2015
- Watch: Fast N Facts @ 7:30pm
- CBSE Board Class 12th Exam Results 2015 declared
- Jaipur girl Mini Rajpal wins Miss India Deaf 2015!
- Dawood's intercepted phone calls prove yet again he is in Pakistan
- One year of Modi govt: How satisfied is the common man?
- Delhi's 2015 CBSE Class 12 topper M Gayatri talks to Zee Media
- Mumbai architecture creates double decker bus from scrap!
- One year of Modi govt: How satisfied is the common man? Part-2
- One year of Modi govt: PM addresses mega rally in Mathura
- No respite from heat for next three days: IMD
- Growing medical negligence in Delhi's AIIMS
- Police registers case after parachute-like objects were spotted over Mumbai airport
- IPL 2015 Final: MI vs CSK - As it happened...
- Heatwave claims over 550 lives so far, Delhi saw hottest day
- IPL 2015 final: Mumbai Indians thrash Chennai Super Kings by 41 runs to lift second title
- Check cbseresults.nic.in for CBSE Class 12 result 2015
- Mathura rally: PM Modi slams 'corrupt' UPA regime, lauds NDA govt's efforts in past one year
- PM Narendra Modi's Mathura rally: As it happened
- CBSE Class 12 results out: Here's how you can check
- Public rally on 100 days of AAP govt: As it happened
- Kejriwal lists AAP govt's achievements of 100 days, slams Centre's 'dictatorial attitude'