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The Castles of my mind 

Genealogy and Genetic Study Website

 

Surnames Site Map Genetics Home

 

Explaining the cell 

In very simple terms

 

(all drawings are not to ratio - just  comparisons)

Not all the parts of a cell are pictured or talked about here........

 

Size of sperm exaggerated

 

The cell in the process of conception

 

 

The cell

 

 

 

 

Inside the cell is the nucleus where the 23 pair of chromosomes reside. Also inside the cell but not in the nucleus is the MTDNA.

 

the nucleus of a cell

 

Here I have used different colors to indicate the 23 pairs of chrosomes. Notice the pair that is not the same color. A blue and a pink?  those are not the same color because they are not the same even though they are a pair. They represent the Y and the X chromosome. A pair but not the same. The others are the 22 pairs of Autosomal chromosomes.  The autosomal chromosomes combine and recombine at each conception. When the egg impregnates, the autosomal chromosomes of the egg and the sperm do a little dance with each other and combine with the same Markers. While some SNP markers are discarded others remain in segments.  (It is all random) The 23 and me test looks for segments that are a certain size and and larger.

 

While the autosomal chromosomes do their little dance, the Y and X pair up; but if a girl child an XX instead of YX, then they do a dance of recombination too. 

 

Now since the Y chromosome has no one to combine/recombine with, he virtually stays the same with very few changes in any of the different markers within the chromosome. Mutations or changes in the markers is always random and happen at different rates for different markers. Changes do happen, faster with the STR markers then with the slower changing  SNP markers.

 

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The MTDNA

A chromosome but very different

 

The MTDNA has a primary job that is as important as the genetic history of the cell, but much different. MTDNA as you can see from the pictures does not reside in the nucleus. It is within each individual cell. MTDNA's job is the creation, direction and use of energy, without energy .. our cells would die! 

While the shape of any of the nucleus chromosome pairs is a string, the shape of the mtdna chromosome is circular. it has about 17000 base pairs that are tested. The tested areas are normally HVR1 and HVR2 and the rest is coding zone. If you look at a clock HVR1 and HVR2 are from 11:59 to about 12:06 the rest of the clock is coding zone.

 

Hope this helps as some people understand better when they can see or picture the item. 

 

 

 

 

 

 

 

 

 

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Contact Information   

Postal address

Nelda L. Percival

644 Warbonett Road, Roach, MO, USA  - 65787

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General Information & Webmaster: nelda_percival@hotmail.com

Copyright 2005 Castles of your mind Genealogy
Last modified: April 09, 2011

 

 

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We all pay a price for it

United States Army

1973-1987

Medical Retirement

 

 

Items below this line are not part of this website.

Rootsweb.com provides the webspace, Ancesrty.com  owns and supports rootsweb, thus visiting the links once in a while helps support the use of free genealogy on rootsweb.com