Reescribirían teeth human history – El Universal

Throughout evolution the size of teeth has been declining, continues even in modern humans, with smaller teeth than their ancestors, such as australopithecines. But what is 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 that come 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 fossil hominids is set to predictions of a single rule simple and elegant development called ‘inhibitory cascade’ “says Gary Schwartz, co-author of this work and paleoanthropologist at Arizona State University (EU).

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

However, this starts before: the general rule is that a molar that develops before has an influence on a molar that makes it later. As the molars grow rather than permanent, this means that the teeth also have an influence on the size of the permanent teeth.

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

While the rule of “inhibitory cascade” is fulfilled in the first hominids and members of the genus Homo, scientists do establish two distinct patterns. australopithecines and another one for 2.8 million years ago, when placed gender Homo

Thus, according to this pattern, the first hominids, known astralopitecus collectively as -the 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 mouth (permanently the greater the second or third molars, also called wisdom teeth).

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

Thus, in species with very large teeth, the largest molar is the third (or wisdom tooth), while species with very small teeth the third molar is 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, ribs or fingers, says Aida Gómez Robles, of George Washington University, in an opinion article also published in Nature systems .

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