Scientists have discovered a new way to determine the average ages at which men and women reproduce all of the time History of human evolution.
By studying DNA mutations in modern humans, they have discovered a window that allows them to peek back 250,000 years.
“Through our research on modern humans, we’ve noticed that we can predict the age at which people will have children from the types of DNA mutations they left for their children,” Says Study co-author Matthew Hahn, a genomics scientist at Indiana University Bloomington.
We then applied this model to our human ancestors to determine the age at which our ancestors had children.
They found that over the past 250,000 years, the average age for humans to have children was 26.9 years. (for context, 300,000 years ago It’s also about when our species first appeared.)
average Homo sapiens Dad was always older than average Homo sapiens Mother, the study found, with Men become fathers She is 30.7 years old, compared to 23.2 years for women.
The researchers added that the age gap has diminished in the past five thousand years, noting that the latest study estimates indicate the average age at Women become fathers Now 28 years old. They suggest that this trend is largely driven by women having children at an older age.
apart from the latter High maternal ageHowever, the study found remarkable consistency in the average age of new parents throughout our species’ existence. It has not increased steadily since prehistoric times, the team says, although it has fluctuated over time.
The average age at conception appears to have declined around 10,000 years ago, and since that would roughly coincide with the advent of agriculture and the dawn of civilization, the researchers say it may be related to the rapid population growth at that time.
Recorded history is only a few thousand years old at best, and it is difficult to glean extensive population-level information like this from archaeological evidence alone.
But The secrets of our ancestors Also lurking inside each of us today, and this is how Han and his colleagues found a way to determine the age of parents to date in time.
The new study takes advantage of the discovery of de novo mutations — DNA changes that appear for the first time in a family member, and that appear spontaneously rather than being inherited through the family tree.
While working on another project involving these New genetic changes and parents of known agesThe researchers noticed an interesting pattern. Based on data from thousands of children, the pattern and numbers of new mutations that form in parents before being passed on to their children depends on each parent’s age at conception.
This allowed the researchers to estimate the generation times of separate males and females across 250,000 years.
“These mutations from the past accumulate with each generation and are found in humans today,” Says Study co-author and Indiana University geneticist Richard Wang.
“We can now identify these mutations, see how they differ between parents, and how they change according to the age of the parents.”
The researchers note that previous research has also used genetic evidence to estimate generation length over time, but it has typically relied on comparisons between modern DNA and ancient samples averaged between sexes and across the past 40,000 to 45,000 years.
“The story of human history has been pieced together from a variety of sources: written records, archaeological finds, excavations, etc.” Says.
Our genomes, the DNA found in each of our cells, provide a kind of manuscript for the history of human evolution.
“The results of our genetic analysis confirm some of the things we have known from other sources, but also provide a richer understanding of ancient human demography.”
The study has been published in Science advances.