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My sisters and I look so different from one another... why is that?
First of all, I would like to make it clear that we are all from the same parents. No adoption or whatever. But it's always been strange how different we all look from one another even though we are all born the same. The best way I can put it is that it's like a colour scale with our hair, eyes and skin tone. My youngest sister has light, blonde curly hair with blue eyes and really pale skin. We used to make jokes about it because she was so pale. She basically only a shade off the colour white itself. However my other sister has black hair frizzy, really dark skin (like an African American) and really brown eyes. People often question if she's black but our family is all very Caucasian. However despite this she turned out so dark which she has no problem with. She often goes around declaring she's black anyway and is very proud of her skin tone. And then there is me. I have green/hazel eyes, medium/light tone skin and brown hair. So I sort of fall in the middle between the too. We are all pretty much the same height and all appear the same age when we go out and most people always seem to assume we are all best friends. They seem completely shocked when they learn we are sisters. My mum and dad both have similar features to one another. Dark brown hair and green eyes with about my skin tone. How does this happen exactly...?
3 Answers
- Anonymous8 years ago
Nature is absolutely amazing when it comes to reproduction. There is a system specifically designed to make children different.
A person has a set of chromosomes. Each chromosome contains two halves that join in the middle so they look like an "X." All that a chromosome is, by the way, is two very tightly coiled strands of DNA (deoxyribonucleic acid).
The two halves of each chromosome come from the two parents. One half of the "X" in each chromosome comes from the mother, and the other half comes from the father. The two halves are bonded together at the middle of the "X." Each half of the "X" contains a complete set of genes, so each chromosome has two copies of every gene -- the "dominant" gene of the two is the one that is expressed.
A sperm and an egg meet to create a new person. The sperm carries one half of the new person's ultimate chromosomes, and the egg contains the other half.
The question then comes down to, "Where does the DNA in the sperm and the egg come from?" Every cell in the father contains a complete set of X-shaped chromosomes that are exactly alike. Same for the mother. The father's chromosomes came from his mother and father, and the mother's from her mother and father. To make a sperm cell, only one half of the X is contributed. But which half? This is where nature does the especially amazing part. When forming sperm cells, the father's body randomly chooses genes from the two halves of the father's chromosomes. This means that every sperm cell contains a random mix of the father's parents' genes. The same thing happens when forming eggs. Therefore, each child that a couple produces is a random mix of the four grandparents' genes.
Source(s): http://science.howstuffworks.com/ - Anonymous8 years ago
The Milkman?
