What very old teeth can tell us about how our ancestors aged

Embargoed until: Publicly released: 2024-11-14 03:00

International

Credit: Vincent Beyrand and Paul Tafforeau, European Synchrotron Radiation Facility, Grenoble, France

Early human ancestors may have had a combination of ape-like early maturity and human-like delayed development, according to an analysis of 1.77-million-year-old fossilised teeth from Georgia in Eastern Europe. The team used advanced imaging techniques to analyse the teeth of an early Homo individual, who died shortly before reaching dental maturity at approximately 11 years old. They found that tooth growth rates were high, similar to rates in living great apes. However, the individual showed a human-like delayed development of the back teeth relative to the front teeth and a late growth spurt of the teeth. The team say their findings suggest that early Homo had evolved an extended growth phase before a general slow-down of life history, possibly related to biological and cultural aspects of life, rather than brain growth.

Media release

From: Springer Nature

Evolution: Hominin teeth reveal extended growth in early humans (N&V) *IMAGE & VIDEO*

Early hominins may have had a combination of ape-like early maturity and human-like delayed development, according to an analysis of 1.77-million-year-old fossilized hominin teeth from Dmanisi, Georgia, published in Nature. The findings offer insight into the growth processes of our ancient relatives

Human life is marked by several unique features, including prolonged childhood and delayed maturation compared with our closest living relatives, the great apes. Teeth have an important role in understanding the history of evolutionary changes because they preserve incremental growth patterns that can be used to infer developmental rates and timings. Human teeth are known to mature slower than great ape teeth, especially permanent molar teeth, which correlates with the pace of brain development and body maturation across primates. The Dmanisi fossils, dating back to 1.77 million years ago, represent some of the earliest members of the genus Homo outside of Africa and offer an opportunity to investigate the growth processes of early humans.

Christoph Zollikofer and colleagues used advanced imaging techniques to analyse the dental microstructure of an early Homo individual from Dmanisi, who died shortly before reaching dental maturity at approximately 11 years old. They found that tooth growth rates were high, similar to rates in living great apes. However, the individual showed a human-like delayed development of the back teeth relative to the front teeth and a late growth spurt of the teeth. The unique combination of great ape-like and human-like features of dental development suggests that early Homo had evolved an extended growth phase before a general slow-down of life history, possibly related to biocultural reproduction (involving both biological and cultural aspects) rather than brain growth.

The findings suggest that the growth patterns of our ancestors may have been more variable than previously thought.

Multimedia

Virtual reconstruction of dental development

Journal/
conference: Nature

Research:Paper

Organisation/s: University of Zurich, Switzerland

Funder: Support was provided by European Synchrotron Radiation Facility (ESRF) grants EC-022 and EC-767 to C.P.E.Z., P.T., M.S.P.d.L. and D.L., by Swiss National Science Foundation grant CR32I3_166053 to C.P.E.Z., and by an open-access publication grant from the Dietrich-Schindler-Stiftung. Support to D.L. was provided by the Georgian National Science Foundation, the National Geographic Society and the L.S.B. Leakey Foundation.

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