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Question:
Could you explain why we could be similar in appearance to our parents but not resemble either one exactly?



Replies:
Because of the process of meiosis or gamete formation (ie. the formation of eggs and sperm). A human being has 46 chromosomes in each cell. We all started out as one cell with 46 chromosomes, 23 came from mom and 23 from dad. During egg and sperm formation, only half of the chromosomes make it into an egg or a sperm. If this didn't happen, each succeeding generation would have double the chromosome number its parents had. So, only half the traits make it into an egg or a sperm also. Which half is random. Also, you are half your mother (her egg) and half your father (the sperm). You must also take into consideration dominance vs. recessiveness. When each parent contributes a version of a trait, sometimes one gives a dominant form and the other gives the recessive form. The recessive form of the trait is hidden by the dominant one. Some offspring look more like one parent or the other because one contributed more dominant traits than the other at random. By mixing up the genetic material in the process of meiosis this allows a species to "try out" new combinations and also to be able to adapt to new environments.

Van Hoeck



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