Mar 12, 2015

Mothers' Day: Reasons to Celebrate

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Given that Mothering Sunday is nearing, we've collated some recent, health-related stories involving the very people who brought us into the world (albeit with a bit of help from a 'friend'...)

Mothers: Can't live with 'em, can't [have] lived without 'em.

Metaphorically speaking, mothers, for so many reasons 'get under our skin' - and vice versa of course. But did you know this literally, as well as metaphorically, the case? Babies spend an average of 9 months 'under the skin' of their mother, yet, new studies on mice have proved that foetal DNA can enter a mother's brain, and remain there for decades! Indeed, some believe the presence of foetal DNA in the brain of mothers may be linked to certain neurological disorders, such as Alzheimer's, a disease that is more common in women who've had children. Watch this space for more news on the subject in due course.

CALL AND I'LL COME!

Meanwhile, what are the key attributes of 'a mother's mind'? For mammalian mothers, NewScientist points to that all-important instinct to rush to a crying infant. But did you know that mammalian mothers will not only respond to infant cries of their own, but to other mammal species? To we humans, this may come as no surprise, especially if you're a cat or a dog owner. Yet, a Canadian study has proved the same is true of wild animals, specifically, mule deer out on the Prairies, which have been observed going to the 'rescue' upon hearing audio recordings of infant cries from seals, dogs, cats and humans, which happen to have a similar pitch. On a deeper level, this study suggests that many mammals experience similar emotional responses.

ELEPHANTS: MEET THE MATRIARCHS

Yet it isn't just mothers, but grandmothers, who play an important role within mammals as social animals. Elephants are well known to have a fascination with their dead, and have been observed in groups, as if attending a funeral. The same journal points to the death (at the grand age of 50) of Eleanor, a Kenyan elephant whose death was marked over nearly a week by visitors to her carcass - not only from her immediate family, but from four unrelated families. It is mooted that elephants' preoccupation with death may be related to the seniority of the deceased, particularly in a mammal group that relies on the elder stateswomen: the matriarchs. Certain studies have showed that humans live to a riper age if they have regular mealtimes with more than just two generations.

grandmother baby

GRANDMOTHERS: A GOOD 'INVESTMENT'

Evolutionary biologists have wondered for years why women tend to live long beyond their reproductive years, with one hypothesis being that grandmothers play an important role in helping their grandchildren survive childhood. After all, human infants are born in a highly immature and vulnerable state compared to other mammals which can stand on four legs within hours or days. (This is apparently due to our two-legged status, which prevents women's hips from being any wider, in turn preventing babies' brains and heads from growing any larger - or risk failing to fit through the pelvis.) In other words, a mother's resources can be highly stretched by her baby (let alone any older children) meaning grandmas can be crucial in their nurture - or in coming to the rescue!

THE SELFISH GENE

Another theory is that grandmothers survive beyond their reproductive years in order to ensure their genes are passed onto more than just one generation. (Think of Richard Dawkins' book from 1976 The Selfish Gene, and you have the concept.)

A Cambridge University study has recently looked at the role of grandmothers on survival of offspring, based on the fact there are genetic biases involved in passing on their genes: Grandmothers share an equal amount of DNA with any sons and daughters of their daughters. But when it comes to their son's sons, they share less DNA than with their son's daughter. (This is to do with how X chromosomes are passed down the generations.) The Cambridge team tested the theory that paternal grandmothers invest less in these grandsons than these granddaughters, (consciously or unconsciously) by comparing life expectancies: They looked at births and deaths records since the 17th Century, from seven countries (to rule out cultural biases). Sure enough, it turned out the males died earlier if they'd grown up with their paternal - rather than their maternal - grandmother, a pattern not seen with the girls. This was in theory due to different levels of input in those children, in terms of education, nourishment, and so on.

There is no doubt that we will continue to find out more about the role, biology and evolution of mothers, as science progresses and is disseminated.

In the meantime, we wish you all a Happy Mothering Sunday. Be grateful. And don't forget the flowers!