Eleanor McBain- May 5- 3/3 Blog #1

In today's class, we wrote a test on Mendelian Genetics. Gregory Mendel used pea plants to determine factors of genetics. The Austrian monk defined alleles, which are an alternate form of a gene controlling a characteristic and also homozygous, heterozygous, dominant, recessive, genotype and phenotype. Also he made two laws ( which means they haven't been disproved yet), the Law of Segregation (separation) and the law of Independent Assortment. He also showed that chromosomes can have multiple alleles, incomplete dominance, co-dominace and the genotype and phenotype can be found using a punnet square. When using the multiple alleles in the punnet squares (dihybrid crosses), it can be quite confusing. It is where I had the most difficulty. My question is how could Gregory Mendel find out all of this information in the early 1800s?

Well, Mendel would grow the plants and then crossbred whatever pea plants by putting them together so that fertilization would occur and kept very good notes about all his findings.

This is a monohybrid punnet square showing the crossing of 2 true (homozygous) pods. This shows that the green colour is dominant to yellow (G= Green, g= yellow)

The green pod is homozygous dominant(GG) and the yellow pod is homozygous recessive (gg)

The next cross shows the crossing of the F1 generation. This shows that both of the parents are heterozygous (Gg) and therefore produced a yellow pod.

The next cross shows a dihybrid cross, that means it can determine 2 traits

This dihybrid square shows the crossing of a pea plants that are heterozygous for the colour (Gg) and also heterozygous for the colour of the seeds (Yy)

It shows that:

9/16 will have green pods and yellow seeds (56%)

3/16 will have green pods and green seeds(19%)

3/16 will have yellow pods and yellow seeds (19%)

1/16 will have a yellow pod and green seeds.(6%)

These are the first experiments of Gregory Mendel and his pea plants.