A single rule governing the development of teeth in the genus Homo and before – W Radio

Madrid, 25 February (EFE) .- Throughout evolution the size of the teeth has decreased even continues in modern humans, smaller than their ancestors, such as australopithecines teeth. But what has regulated and regulates the size of the teeth ?: “same and simple” rule development.

The researchers, led by Alistair Evans of Monash University (Australia) they have called this “elegant” rule “inhibitory cascade ‘, according to which the size of each tooth is regulated by the amount of activator and inhibitor molecules coming from the tooth develops before it.

a greater amount of inhibition by a molar, which develop later will be smaller, and vice versa.

the conclusions of this study are published this week in the journal Nature.

“One of the most interesting finding of this new study is that the size of the teeth, including molars, in modern humans and hominid fossils fits the predictions of a single rule simple and elegant development called ‘waterfall . inhibitory ‘ “says Gary Schwartz, co-author of this work and paleoanthropologist at the State University of Arizona (USA)

in a note at the university, the researcher Susanne Daly added: under this simple rule formerly observed in mice-the size of a molar is regulating the development of its neighbors, thus limiting the size of the teeth later in development

However, this starts earlier. the general rule is that molar that develops before has an influence on a molar making it later. As molars grow before permanent, this implies that the teeth also have an influence on the size of the permanent teeth.

To reach these conclusions, fossils of teeth examined . hominids for the last 5 million years

While the rule of “inhibitory cascade ‘is fulfilled in the first hominids and members of the genus Homo, the scientists did establish two distinct patterns: one for Australopithecus and another 2.8 million years ago, when placed to the genus Homo.

Thus, according to this pattern, the first hominids, collectively known as -the astralopitecus best example is “Lucy”, a member of the species “Australopithecus afarensis” – had larger teeth in general and larger molar was located closer to the back of the mouth (permanently, the greater the second or third molars, also called wisdom teeth).

but the fossil remains of our own genus not only reveal that they had smaller teeth, the molars but vary according to the size of the teeth (the relative sizes of the wheels began to depend on total size of the dentition).

Thus, in species with very large teeth, the largest is the third molar (or wisdom tooth), while species with very small teeth third molars is more smaller than the rest.

the results are relevant beyond the study of fossil teeth as these teeth may be useful to identify mechanisms that operate in other formed by the repetition of elements such as vertebrae systems, ribs or fingers, says Aida Gómez Robles, of George Washington University, in an opinion article also published in Nature. EFE