The RULE OF SEGREGATION (Separation)

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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 below. 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.

 

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.

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