The female genetic Advantage

Women tend to live longer than men. Women have stronger immune systems. Women are less likely to suffer from developmental disability. Women have better color vision than men. Less women die of cancer and most other leading causes of death than men.

At birth; slightly more male babies than female babies are born. However, as we progress through the decades women outnumber men in the ultra-marathon of life and get this...not just in life, even in actual marathons, women are more likely to prevail in ultra-marathons! The longer the race, the likely women are to prevail in it!

is the extra X chromosome responsible for all this??read on to find out.

Females have two X chromosomes and men have one X chromosome.

Females= XX and Males=XY

The X chromosome has nearly 1000 genes in it!

The Y chromosome has about 70 genes!

Why do we have two of each chromosome? redundancy is one reason. If there is something wrong with one gene, the other gene can act as a backup. If you have fully working copies in both the original and backup genes then good for you. You get the full bang for the buck from both chromosomes.

Think of it in terms of twin engine aircraft. If something goes wrong with one engine, the other engine can save your life. However, if both are working fine, then we enjoy a smooth ride and get to our destination at full speed.

If there is something wrong with the genes on the X chromosome, men are screwed, they have no backup, whereas women are covered by the backup.

Females enjoy the following genetic advantages because of the two X chromosomes they carry:

1) The Immunity edge:

X chromosome contains a high density of immune-related genes and regulatory elements that are extensively involved in both the innate and adaptive immune responses. Females have better immunity owing to an aggressive immune system. But there are two sides to the immunity coin. A hyperactive immune system means women are more prone to autoimmune conditions such as Multiple Sclerosis.

2) Females are protected from color blindness and can see up to 4 colors:

Red-green color blindness?is linked to the X chromosome. People who have it can see normally, but can’t distinguish shades of red and green. It occurs in about 1 in 12 males but only 1 in 200 females.

The gene to distinguish color sits on the X chromosome. People with normal color vision have three types of cone cells, which allow them to perceive about a million shades of colors. Some women have four types of cone cells, which allows them to perceive a staggering 100 million shades of colors! The best a man can hope for is to be able to see three colors. Women can see up to 4.

3) Protection from Blood clotting disorders:

The genes for clotting factor control reside on the X chromosome. Clotting factor disorders such as Hemophilia A and B affect males.

4) Protection from developmental disability:

Boys are 4 times more likely to be diagnosed with Autism spectrum disorder. Boys are twice as likely to face developmental disabilities in general. More than 100 genes in the X chromosome has been associated with intellectual disability collectively known as X-linked intellectual disabilities.

There are a host of other conditions that trace their origin to the X chromosome and women are protected from these https://en.wikipedia.org/wiki/X-linked_recessive_inheritance

5) Protection from Muscular Dystrophy:

Duchenne Muscular Dystrophy is associated with a mutation of a gene on the X chromosome, the DMD gene, which encodes dystrophin, the muscle protein.?

6) Protection from Hemochromatosis:

Hemochromatosis is an excessive iron disorder caused by genetic mutations. Because women lose blood through menstruation, they are protected from excessive iron disorders. On the flipside, they are vulnerable to iron deficiency as well.

7) The longevity edge:

On average women outlive men by at least four to seven years. Women over the age of eighty-five, outnumber men two to one. Out of one hundred centenarians alive today, eighty are women and only twenty are men. Among supercentenarians—people aged 110 years and above—95 percent of them are women. Women's longevity edge persists even adjusting for factors like risk taking, education, occupation (comparing monks and nuns), smoking, drinking etc.

Note: The advantage of having two X chromosomes is not just in humans. Birds have the opposite sex chromosome system to humans, meaning, Females have one Z chromosome and males have ZZ chromosomes. In birds, males have the advantage.

This article was inspired by the book "The Better Half : On the genetic superiority of women "by Moalem, Sharon.

https://www.amazon.com/Better-Half-Genetic-Superiority-Women/dp/1250174783