ScienceDaily, April 30, 2012
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| A Finnish family featured in the research. (Credit: Image courtesy of University of Sheffield) |
New evidence proves
humans are continuing to evolve and that significant natural and sexual
selection is still taking place in our species in the modern world.
Despite
advancements in medicine and technology, as well as an increased prevalence of
monogamy, research reveals humans are continuing to evolve just like other
species.
Scientists in an
international collaboration, which includes the University of Sheffield,
analysed church records of about 6,000 Finnish people born between 1760-1849 to
determine whether the demographic, cultural and technological changes of the
agricultural revolution affected natural and sexual selection in our species.
Project leader Dr
Virpi Lummaa, of the University's Department of Animal and Plant Sciences,
said: "We have shown advances have not challenged the fact that our
species is still evolving, just like all the other species 'in the wild'. It is
a common misunderstanding that evolution took place a long time ago, and that
to understand ourselves we must look back to the hunter-gatherer days of
humans."
Dr Lummaa added:
"We have shown significant selection has been taking place in very recent
populations, and likely still occurs, so humans continue to be affected by both
natural and sexual selection. Although the specific pressures, the factors
making some individuals able to survive better, or have better success at
finding partners and produce more kids, have changed across time and differ in
different populations."
As for most animal
species, the authors found that men and women are not equal concerning
Darwinian selection.
Principal
investigator Dr Alexandre Courtiol, of the Wissenschftskolleg zu Berlin, added:
"Characteristics increasing the mating success of men are likely to evolve
faster than those increasing the mating success of women. This is because
mating with more partners was shown to increase reproductive success more in
men than in women. Surprisingly, however, selection affected wealthy and poor
people in the society to the same extent."
The experts needed
detailed information on large numbers of study subjects to be able to study
selection over the entire life cycle of individuals: survival to adulthood,
mate access, mating success, and fertility per mate.
Genealogy is very
popular in Finland and the country has some of the best available data for such
research thanks to detailed church records of births, deaths, marriages and
wealth status which were kept for tax purposes. Movement in the country was
also very limited until the 20th century.
"Studying
evolution requires large sample sizes with individual-based data covering the
entire lifespan of each born person," said Dr Lummaa. "We need
unbiased datasets that report the life events for everyone born. Because
natural and sexual selection acts differently on different classes of
individuals and across the life cycle, we needed to study selection with
respect to these characteristics in order to understand how our species
evolves."
The
project was funded by the European Research Council and the Kone Foundation
(Finland) and was carried out with Wissenschftskolleg zu Berlin and the Leibniz
Institute for Zoo and Wildlife Research in Germany, University of Turku in
Finland, University of Helsinki in Finland, and the Population Research
Institute in Finland.
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Journal Reference:
- Alexandre Courtiol, Jenni E. Pettay, Markus Jokela, Anna Rotkirch, and Virpi Lummaa. Natural and sexual selection in a monogamous historical human population. PNAS, April 30, 2012 DOI: 10.1073/pnas.1118174109
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