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+--- Thread: Why tall women and short men are becoming a thing of the past (/thread-9337.html)
Why tall women and short men are becoming a thing of the past - C C - Nov 10, 2020
https://www.dailymail.co.uk/health/article-8931041/Why-tall-women-short-men-thing-past.html
EXCERPTS: Tomorrow’s woman is short and has a small head. Her narrow mouth sits beneath prominent cheekbones. She is a winner in the fertility stakes, entering menopause at a later age than her gran. Tomorrow’s man, meanwhile, is taller and less inclined to become a heavy smoker than today’s model. This is the direction in which we are rapidly evolving, according to studies of newly emerging genetic mutations. Some of these include oddities, such as people having an extra artery in their forearms and unusually bony feet.
[...] anatomists at Flinders University in Australia [...suggest...] we are experiencing a rapid burst of change called a micro-evolution, where modern life exerts pressures that influence our genes to mutate. One of the most obvious is how increasing numbers of people are born without the capacity to grow wisdom teeth, says Dr Teghan Lucas, who led the research, published in the Journal of Anatomy last month.
Our caveman ancestors needed them to replace other teeth worn down by tearing raw, chewy food. But as humans learnt to cook, they needed to chew less. So around 2.4 million years ago their jaws shrank, making space for the modern human brain to expand. According to Dr Lucas, our jaws are still changing, perhaps due to the amount of processed food in modern diets, which requires even less chewing. ‘As our faces are getting a lot shorter, there is not as much room for teeth because of smaller jaws,’ she wrote.
[...] In April, a study in the journal BMC Women’s Health concluded that women may soon stay fertile significantly longer, in response to pressures that push them to have babies later in life. Dr Rama Shankar Singh, a professor of biology at McMaster University in Canada, says his study of more than 700 middle-aged women from six ethnic groups suggests there are no concrete biological mechanisms that force human menopause to occur at a particular time in a woman’s life. Instead, modern social forces, such as delayed marriage and reproduction, may well push menopause back to occur much later in life. ‘Menopause is a changing, evolving trait that is still very dynamic,’ says Professor Singh.
Mark Thomas, a professor of evolutionary genetics at University College London, says such changes are typical of how humankind is evolving, particularly in the sphere of fertility. He adds that evidence from the UK Biobank data on more than half a million people and their DNA shows that in the past generation alone, genes that prompt a shorter height in women are becoming more dominant. Men, meanwhile, are getting taller. But why this might be so is not clear.
Even our diet can affect our genes. Scientists from Cornell University, New York, have discovered how families who practise vegetarianism for generations evolve a mutation of a digestive gene called FADS2. This enables them to efficiently process omega-3 and omega-6 fatty acids from non-meat sources into essential brain nutrients, they reported in the journal Molecular Biology and Evolution in 2016.
However, while some health-boosting habits are encouraging specific genes to proliferate, other genetic types are being erased because of their link to unhealthy lifestyles... (MORE -details)