For about 250,000 years, men become parents later than women

When will we be parents? According to a published study Advances in science, men give birth to their first child later than women. Researchers from Indiana University in Bloomington, USA, came to this conclusion. For this, they analyzed DNA mutations in modern people. This allowed them to jump back 250,000 years.

The importance of knowing the duration of human generations

Knowing at what age our ancestors became parents allows us to have a fairly accurate idea of ​​the duration of human generations. This information can tell us about both the biology of our ancestors and their organization. Genetic information provides a better understanding of human history. In contrast, population genetics methods allow us to estimate history in terms of generations. Generation time allows us to determine the absolute chronology of the various events that punctuate history. This allows, for example, to study the migration flows that have occurred in the history of mankind.

What is generation? The term generation is a concept used in demography. It defines a population, or more precisely a sub-population, of people who are of the same age and lived in the same period of history. In the last century, the German philosopher and theologian Wilhelm Dilthey (1833-1911) gave an interesting and still relevant definition of generation.

“Despite the diversity of other factors, a rather narrow circle of individuals who are bound into a homogeneous whole because they depend on the same great events and changes that took place during the period of receptivity. »

We know that a generation is about 25 years old. This is the length of the renewal period of an adult population capable of reproduction. It can also be the average time between a person’s birth and the birth of their child.

Also read: Meet DNA.LAND, the world’s largest human genome analysis project

Fathers are always older than mothers

During cell division, DNA is transferred to daughter cells.
Credit: Pixabay.

A research team at Indiana University created a model of sorts. So they worked from a panel of about 1,500 people and from information from their parents. This information included, among other things, the age of the parents at birth. We also found possible genetic changes over three generations. This preamble allowed them to link certain types of DNA mutations, as well as their frequency after becoming parents for the first time, to people’s gender and age.

The researchers then used this model to apply it to our ancestors. They were trying to determine how old their first child was. They found that over the past 250,000 years, the average age for humans to have their first child was 26.9. More precisely, in 250 thousand years, men become fathers at the age of 30.7 years, and women at the age of 23.2 years.

However, over the past 5,000 years, this gap between men and women has narrowed somewhat. Research shows that the average age of women having their first child today is 28.

Despite this increase, the researchers noted that, as our species has existed, the average age of new parents can change over time. However, it has not increased steadily. Moreover, since the beginning of mankind, fathers have always been older than mothers.

Also read: Can a man get pregnant?

Parents pass on mutations to their children

The researchers came to this conclusion by analyzing various mutations found in children. A genetic mutation is a change in genetic information. The cells that make up a person are constantly dividing to replace the cells of that age. During these cell divisions, DNA is replicated and an identical copy is transferred to each daughter cell. In some cases, an abnormality in a gene may occur during this replication, which is a genetic mutation. In most cases, the human body can eliminate this defective gene with a certain mechanism without any consequences. In other cases, the mutation does not repair itself and can then be passed down from generation to generation.

For many people, genetic mutation rhymes with genetic disease. Fortunately, not all mutations result in genetic disease. Rather, in most cases they simply result in variations that mark each person’s individuality.

There are also mutations that appear spontaneously in an individual and are therefore not transmitted by parents. These mutations are called de novo mutations.

The researchers analyzed data from thousands of children. They observed that the type and number of new mutations that occurred in parents before being passed on to their children depended on each parent’s age at conception.

The age of the father is almost always older than the age of the mother when the first child is born. This is explained by the fact that men can reproduce much later than women.

Also read: Mutations in the animal kingdom shed new light on aging

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