Sunday 21 March 2010

Mendel's Law of segregation | Gene Transmission


Genes are located in chromosomes and consist of DNA and so are passed from parents to their offspring through reproduction.

Mendel worked with pea plants and selected seven traits to study that each occurred in two different forms. One of those traits were pod colour, as some pea plants are green and others yellow and since pea plants can self fertilize, Mendel was able to produce true-breading(a yellow pod plant would only produce yellow pod offspring) plants. Mendel's experimentation lead him to discover what would happen if he were to crossed a true-breeding yellow pod plant with a true breeding green pod plant. He referred to the parental plants as the P generation, and the offspring were called the F1 generation.


After Mendel cross-pollinated the true breeding green and yellow pods, the offspring (F1 generation) were green. Then Mendel let the F1 plants self pollinate and these offspring were named the F2 generation. The results came out to be that about 3/4 of the offspring of the F2 generation were green and the 1/4 yellow. These experiments let Mendel come up with his law of segregation.


This law of segregation puts across that allele pairs separate during gamete formation and randomly unite at fertilization. This ides leaves different concepts like 1, there are alternative forms of genes which means that a gene can exist in more than one form. 2, when sex cells are produced allele pairs segregate, which leaves them with a single allele for each trait. Also, when two allele pairs are different one is dominant and the other is recessive, like shown in the illustrated picture above.

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