London: Bizarre it may appear, but having
two mothers may be the key to a longer lifespan -- in mice, at
least, a new study has revealed.
Scientists in Japan have discovered that mice with two
biological mothers but no father live about 30 percent longer
than usual, in an pioneering experiment which they claim could
have implications for understanding human ageing.
While it is not yet known whether the effect applies
to humans also, the research gives new insights into genetic
influences on the ageing process in mammals which might be
eventually exploited to slow it down, `The Times` reported.
It could also illuminate the way that genes provided
by mothers and fathers combine in the embryo, improving
understanding of reproduction and certain diseases, according
to the scientists.
Professor Tomohiro Kono of the Tokyo University of
Agriculture, who led the research, said that it could even
offer clues to why women typically live longer than men.
"The study may give an answer to the fundamental
questions: that is, whether longevity in mammals is controlled
by the genome composition of only one or both parents and,
just maybe, why women are at an advantage over men with regard
to the lifespan," he was quoted as saying.
For the experiment, the scientists created 13
"bimaternal" (BM) mice, conceived from two eggs, and compared
these with 13 female mice of the same strain produced in the
normal fashion and raised in the same environment.
The study found that the BM mice lived on average
for 186 days longer than the normal animals, an increase which
was equivalent to a group of women living to an average age of
105, compared with the current average of 81.
The longer-lived BM mice were significantly smaller
and lighter than the normal ones.
Prof Kono said that the increased lifespans of the BM
mice probably reflected the abnormal way in which their
genomes were imprinted, as they had no DNA of male origin.
This suggests that certain imprinted genes from the
father`s sperm may suppress lifespan, perhaps while also
increasing body size, the scientists said.
The findings have been published in the latest edition
of the `Human Reproduction` journal.