The human parathyroid gland, which regulates the level of calcium in the blood, probably evolved from the gills of fish, according to researchers from King’s College London. Anthony Graham and Dr Masataka Okabe published their findings in the Proceedings of the National Academy of Sciences.
The parathyroid gland and the gills of fish are related structures and likely share a common evolutionary history,’ said Professor Graham. ‘Our work will have great resonance to all those people who have seen Haeckels’ pictures, which show that we all go through a fish stage in our development. This new research suggests that in fact, our gills are still sitting in our throats - disguised as our parathyroid glands.’ Human Gland Probably Evolved From Gills Science Daily 2004-12-07
Pharyngeal pouches and slits
The first pharyngeal pouch grows out between the first and second branchial arches. It’s endoderm ultimately forms the lining of the auditory tube, tympanic cavity and mastoid antrum.
Endoderm of the second pharyngeal pouch forms the surface epithelium and lining of the crypts of the palatine tonsil. Mesenchyme surrounding the crypts differentiates into the rest of the tonsil.
Endoderm of the third pharyngeal pouch differentiates into inferior parathyroids and the thymus. These structures then migrate to their respective locations in the adult.
The fourth pharyngeal pouch endoderm gives rise to superior parathyroid glands and the ultimobranchial body.
Teaching module on gross anatomy of head and neck
See also Pharyngeal arches
During human development the embryo goes through a stage where the head region (Figure 10) resembles that of a fish. During this time “branchia” which resemble gills develop. In fish, the branchial apparatus forms a system of gills for exchanging oxygen and carbon dioxide between the blood and the water. In humans, the arches (Figure 11) develop but no gills form, therefore we prefer to use the term “pharyngeal” instead of “branchial” in describing these arches.
Human parathyroid probably evolved from gills Biochemistry News december 7 2004
Why would someone develop a theory which confirms a fraud?
Joel, could you please be clearer? What is a fraud and what confirms it?
I hate to speak for someone else, but I presume he’s referring to the mention of Haeckel’s pictures, which brings to mind the falsified drawings used to promote his (now discredited) biogenetic law (recapitulation).
While the actual work described above surely does not support the biogenetic law, it’s unfortunate that Graham would choose to invoke Haeckel’s name. This is probably just a case of a scientist making a historical reference that other scientists will understand (Haeckel is forever linked to embryonic pictures, despite the failure of his hypothesis). However, the statement has now become fodder for creationist quote miners.
Nothing really would stop creationist quotemining. What I am concerned about is how creationists see the word Haeckel and respond with ‘fraud fraud fraud’ or even worse. Richardson, who renewed the interest in Haeckel’s work wrote
Wells’ ‘Icons of Evolution’ have done a disfavour to creationists who seem to be still relying on much that was written in it.
The structures exist. What fraud are you referring to? This isn’t that tired old Haeckel canard that morally and intellectually bankrupt Creationists bring up. Whatever Haeckel’s flaws with his charts, pharyngeal arches exist. So please be clear. Are you saying the structures don’t exist, or are simply under the belief that Haeckel’s ideas on ontogeny recapitulates phylogeny are still accepted.
So, please, by all means, tell us what fraud you refer to.
The article is now online for subscribers to PNAS
The origin of the parathyroid glandMasataka Okabe, and Anthony Graham, Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0406116101
The links to the quickie embryology recaps are delightful. Last resd that stuff in 1966, but I think I recollect that the parathyroids were known to arise from branchial pouch structures then.
As to ontogeny recapitulating phylogeny, I had the impression that to a certain extent it does, since we are constrained in our morphology by our evolutionary history. Our embryologic divergence from other species reflects our evolutionary divergence.
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