Now, can you in simple English explain the 2007 findings?
I'm just a forester, but here goes (I'll probably get annihilated by a geneticist, but who can understand those guys anyway?) Do tell me whether it is plain English especially if you are not a geneticist:
Before you were a twinkle in your daddy's eye, you were a haploid (meaning half the possibilities) cell in your mama's tummy, called an egg. Another haploid cell from your daddy, called a sperm, joined up with the haploid cell from your mama, and the two of them together made you, a diploid cell that divided jillions of times into other diploid cells (and they are still doing that to this very day). Thus you became the very fine person that you are.
Genes are like addresses on a street. Every human being has 46 streets called chromosomes, and each street has almost countless (until recently) doors. Some doors contribute to your personal attributes and others do nothing, or at least what they do is unknown at this time.
You knock on certain doors to get your hair color, other doors to get eye color, and so forth. Sometimes you have to knock on more than one door to get a particular attribute. Sometimes several doors will hand out height growth, for example, and they all add up in various combinations that might make you taller than your brother and shorter than your sister.
Each one of these addresses looks the same on the outside and only the street that it is on and the location on the street differentiates one from another in what it does.
If you open the door at a particular address you will see a necklace with four beads, each one of four possible colors.
Let's say the four colors are Red, Green, Blue, and Yellow. The colors on each necklace and their arrangement on the string behind every one of those hundreds of doors on each of 46 different streets called chromosomes is responsible for the difference between you and every other human being that ever lived.
Let's say you knock on the eye color doors. Behind each door you will see four colored beads on a string and some other stuff, same as behind the hair color doors and the doors that add up to make you as tall as you are.
Two of the beads came from your mama and two from your Daddy. Two beads on one side of the gene are called an allele and a gene is composed of two alleles, one on each side, called a pair.
If you have all four colors they can line up in sixteen different combinations: Red Green Blue Yellow; Red Green Yellow Blue; Red Yellow Green Blue, and so forth. Then you have to start counting Red Red Yellow Blue, Red Red Blue Yellow, and so forth. Pretty soon it's a LOT of combinations.
Some combinations are more powerful than others so they get their way no matter what. These are called dominant genes. Other combinations must gang up together in order to get their way. These are called recessive genes. Blue eyed people have an example of this type of gene because both their mama and their papa had a recessive gene for blue eyes even if they themselves did not have blue eyes. It gets more complicated than that, and since I'm already way over my head I'm not going to go into it.
All but one of the 46 chromosomes are the same for both sexes. But your Daddy has an special chromosome that is different from your mama's, called the Y chromosome (which is really short for XY, because your mama's chromosome is XX), and this chromosome is the doodad that smart people study to trace the ebb and flow of population genetics, simply because the Y thingee makes it cheaper and easier to follow the male line than the female.
If you watch CSI you might notice Greg talking about two persons having a particular number of alleles in common, which means that they must be related. When he looks for alleles in common, he goes for certain genes called markers, the address and other attributes of which are known to prove whether a person is related to another.
A haplotype is a bunch of alleles at a specific location and a haplogroup is just a bunch of related haplotypes. If Greg could dig up Thomas Jefferson's body and compare alleles with people claiming or denying being related to him, he would be able to prove or disprove their claim.
Haplogroup K2 is the group of people that are related to Jefferson, no matter who their mamas were.
The biggest haplogroup is the human race, because we all descended from one single woman who lived so long ago that she must have been one of the first human beings. Every human being on earth has one marker gene that is identical to every other because we all got that gene from her, hence we are all related.
I now humbly place my neck on the block and await the axe of the first geneticist who spots my errors. I also humbly apologize for the length of this discourse, but plead the necessity of one of the most complex fields of science known to man. |
