Why Women Are Stripey

by bluesbaby5050 on February 4th, 2015

Why Women Are Stripey.
Inside Each One of Your Cells,
there Is 6 Feet of DNA.

February 4, 2015.
The awesome YouTube video below by Veritasium, Derek Muller explains why women are stripy.

I won’t give too much away, but I’ll briefly introduce the topic of epigenetics for those who don’t know much about it. Epigenetics refers to changes gene activity that occurs without alterations to the DNA sequence itself. Epigenetic modifications can switch genes on or off and determine which particular proteins are produced in different cells of the body.

Epigenetics is essential since all of the cells in your body possess the same DNA sequence, but different types of cell require different proteins to be produced. It is these changes in gene expression that are therefore responsible for the different types of cell found in the body, or cell specialization. Gene silencing (switching off genes) is also important in the inactivation of the second X chromosome found in female mammals so that females don’t produce twice as many X-chromosome gene products as males.

There are a few different ways to silence genes, for example DNA methylation. This process involves the addition of a methyl group to a specific region of DNA, altering its structure and consequently changing the way that a particular gene interacts with the machinery needed to produce RNA, a pre-requisite for protein production.

When a female embryo is four days old it consists of just 100 cells. At this point the x-chromosome from Mom and the one from Dad are both active. But in order for proper development to occur, one of the x chromosomes must be switched off.

Through a tiny molecular battle within each cell, one of the x-chromosomes wins and remains active while the loser is deactivated.

This is done by wrapping the DNA tighter around proteins, modifying histone tails, and DNA methylation - molecular markers to indicate this DNA should not be read.

What's surprising is that it's pretty random which x chromosome wins - sometimes it's Mom's and sometimes it's Dad's. So when a female is just 100 cells big, her cells have a mix of active x-chromosomes, some from Mom and some from Dad. - Check out this video to find out more: https://www.youtube.com/watch?v=BD6h-wDj7bw&feature=player_embedded#t=0


Epigenetics means women have different active x-chromosomes in different cells.
Animation courtesy of http://wehi.tv
Music by Amarante: http://bit.ly/VeAmarante
Animation: Etsuko Uno
Art and Technical Direction: Drew Berry
Sound Design: Francois Tetaz & Emma Bortignon
Scientific Consultation: Marnie Blewitt
Courtesy of Walter and Eliza Hall Institute of Medical Research: http://wehi.tv
- See more at: http://www.forbiddenknowledgetv.com/videos/biology/why-women-are-stripey...

 Filed under: Science


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