Examining the fossil record through the lens of evolutionary developmental biology may help scientists reassess the evolutionary history of humans and other hominins, suggests a new report in the journal Science Advances.
Although the human body has 206 bones, the most durable and long-lasting part of the human skeleton is the teeth. Because of this, they are the most common item found in the hominoid fossil record and are thus a vital resource for paleoanthropology.
Alejandra Ortiz, a post-doctoral researcher at Arizona State University in Tempe, US, has worked with an international team of researchers to apply an evolutionary developmental biology approach to molar morphology.
Affectionately known as ‘evo-devo’, this approach seeks to understand how evolution (changes in species over long timescales) interacts with developmental processes (how individual organisms develop from embryos).
The authors suggest that a single developmental ‘program’ previously known in other mammals such as seals, called the patterning cascade model (PCM), might be responsible for the variation among hominoid molars. PCM postulates that a blueprint for the shape of a mature molar is built from interactions between signalling centres called ‘enamel knots’ during development.
The team analysed 763 molars from six hominoid genera, both living and extinct, and discovered that most of the diversity of the molar cusp landscape can be explained by the PCM.
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