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Segregation
Segregation
Gametes (sex cells) only receive one allele from the original gene.
As you know, 2 alleles control a gene. "Ee" is a gene in the critter to the left. When gametes are produced, the alleles of the gene separate and go into different sex cells; in other words, one letter is packaged in one sex cell and the other letter is packaged in another. Please note that each sex cell contains 50% of the original gene.
Ee = gene of the Hybrid parent.
Hybrid parents will make 2 types of sperm and egg. In this case, E and e.
Why does segregation occur? This separation prevents information-overload in the baby. The baby would be defective if parents passed on both alleles of the gene. 100% + 100% = 200%.
When the sperm fuses with the egg, new, whole genes are created in the baby. 50% + 50% = 100%
When an egg with one letter (50% of a gene) fuses with a sperm with the other letter (the other 50%), a new gene is established and the baby is on the way. When 1 allele in sperm meets the 1 allele in egg, we get a gene with two letters! Think about it this way: 1/2 the information from mom, plus 1/2 the information from dad = 1 normal baby genotype.
Silly question number 1: Why do parents only give one allele, and not all of the information they possess? It prevents information- overload. 2 alleles from each parent would result 4 alleles in the baby- and that would not good.
KEY:
The "E" allele codes for an Excellent creature with 2 eyes.
An "ee" genotype codes for a deformed creature with 1 eye.
Ee: makes 2 kinds of sex cells.
ee: makes one kind of sex cell.
EE: makes one kind of sex cell
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