z-logo
Premium
EXTREME SELECTION IN HUMANS AGAINST HOMEOTIC TRANSFORMATIONS OF CERVICAL VERTEBRAE
Author(s) -
Galis Frietson,
Dooren Tom J. M. Van,
Feuth Johan D.,
Metz Johan A. J.,
Witkam Andrea,
Ruinard Sebastiaan,
Steigenga Marc J.,
Wunaendts Liliane C. D.
Publication year - 2006
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.0014-3820.2006.tb01896.x
Subject(s) - biology , homeotic gene , cervical vertebrae , rib cage , selection (genetic algorithm) , anatomy , cervical rib , evolutionary biology , genetics , phenotype , gene , artificial intelligence , computer science
Why do all mammals, except for sloths and manatees, have exactly seven cervical vertebrae? In other vertebrates and other regions, the vertebral number varies considerably. We investigated whether natural selection constrains the number of cervical vertebrae in humans. To this end, we determined the incidence of cervical ribs and other homeotic vertebral changes in radiographs of deceased human fetuses and infants, and analyzed several existing datasets on the incidence in infants and adults. Our data show that homeotic transformations that change the number of cervical vertebrae are extremely common in humans, but are strongly selected against: almost all individuals die before reproduction. Selection is most probably indirect, caused by a strong coupling of such changes with major congenital abnormalities. Changes in the number of thoracic vertebrae appear to be subject to weaker selection, in good correspondence with the weaker evolutionary constraint on these numbers. Our analysis highlights the role of prenatal selection in the conservation of our common body plan.

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here