Scientists have discovered a new way to determine the average age at which males and females reproduce around the world. human evolutionary history.
By studying DNA mutations in modern humans, they discovered a window that allows them to look back in time 250,000 years.
“Through our research on modern humans, we realized that we could predict the age at which people could have children from the types of DNA mutations that people leave to their children.” says Check out co-author Matthew Hahn, a genome scientist at Indiana University Bloomington.
“We then applied this model to our human ancestors to determine at what age our ancestors reproduced.”
They found that over the past 250,000 years, the average age of people to have children has been 26.9. (For context, 300,000 years ago roughly the period when our species first appeared.)
Average homo sapiens dad has always been older than average homo sapiens mother, the study found, men who are fathers 30.7 years old, 23.2 years old for women.
But the researchers add that the age gap has narrowed over the past 5,000 years, and the study’s most recent estimates suggest average age. women become parents now 28 years old. This trend appears to be driven largely by women who have children later in life.
out of the last time rising maternal ageBut the study found remarkable consistency in the average ages of new parents throughout our species’ existence. The team reported that although it has fluctuated over time, it has not increased steadily since prehistory.
The average age at conception seems to have dropped by about 10,000 years ago, and since this would roughly coincide with the advent of agriculture and the dawn of civilization, the researchers say this may be related to rapid population growth over that period.
Recorded history goes back only a few thousand years at best, and such large, population-level information is difficult to gather from archaeological evidence alone.
But secrets of our ancestors it also lurks inside each of us today, and that’s how Hahn and his colleagues stumbled upon a way to determine parental age back in time.
The new study addresses the discovery of de novo mutations—DNA changes that occur in a family member that arise spontaneously rather than inherited from the family tree.
While working on another project that includes these new genetic changes and parents of known ageThe researchers noticed an interesting pattern. Based on data from thousands of children, the pattern and number of new mutations that occur in parents before they are passed on to children depend on the age at which each parent conceives.
This allowed the researchers to estimate separate male and female generation times over 250,000 years.
“These mutations from the past accumulate with each generation and exist in humans today.” says study co-author and Indiana University phylogeneticist Richard Wang.
“We can now identify these mutations and see how they differ between male and female parents and how they change as a function of parental age.”
The researchers note that previous research has also used genetic clues to predict generational length over time, but is typically based on comparisons between modern DNA and the sexes and ancient samples averaged over the past 40,000 to 45,000 years.
“The story of human history has been compiled from a variety of sources: written records, archaeological finds, fossils, etc.” says.
“Our genomes, the DNA in each of our cells, provide a kind of manuscript of human evolutionary history.
“Findings from our genetic analysis confirm some of what we know from other sources, but also offer a richer understanding of the demographics of ancient people.”
Study published Science Advances.
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