In-breeding is ‘key to male longevity’

MARRYING close family might be frowned upon in civilised society but a scientific study published yesterday appears to have discovered one benefit to in-breeding: a long life.

According to an article in the New Scientist, getting together with a cousin could be the answer to having children who live longer.

Giuseppe Passarino of the University of Calabria in Rende, Italy, who conducted the study, believes in-breeding could provide the key to longevity.

He said: “Everyone knows that in-breeding is bad — it increases your chances of catching a range of diseases.

“But on the other hand, our study suggests that if inbreds don’t get those diseases when they’re young, they might have a better chance of long life.”

Mr Passarino and his colleagues used census data to pick out a geographically isolated region of southern Italy which had more male nonagerians than normal.

His team looked through the local phonebook and found many people in the region shared the same surname, suggesting marriage of relatives was common.

The scientist said it was possible to trace a surname because, like the Y chromosome, it passed down the paternal line.

He believes living longer could be linked to “homozygosity”, where someone has two identical copies of a gene which can occur when the gene pool stays the same.

“This may be because certain copies of some genes boost lifespan, and carrying two of them doubles the effect.

“A number of DNA analyses have located regions of the genome where centenarians show an unusually high level of homozygosity.”

Leonid Gavrilov, from the University of Chicago, said: “It is theoretically possible to observe more centenarians as a result of in-breeding.” But he did question why only men appeared to benefit.

Bruce Carnes of the University of Oklahoma warned against marrying a relative: “Homozygosity is typically a very bad thing. Almost every discussion of in-breeding that I have ever read has emphasised its downside.”

Blood relations

Homozygosity carries enormous health risks:

* Reduced fertility

* Increased genetic disorders

* Fluctuating facial asymmetry

* Lower birth rate

* Higher infant mortality

* Slower growth rate

* Smaller adult size

* Spinal muscular atrophy and diabetes.