Bio3

Question 1

Mendel

Answer 1

Known as the father of genetics, he experimented on pea plants since they grow fast, and have two forms for traits. QHe allowed to plants to self pollinate at first but then halted it it to cross breed them to make hybrids. He called the first generation the parental generation and the second (with all monohybrids) the filial one generation. He concluded that traits were passed on by hereditary units. Genetics is the study of how traits are passed on between generations. His law of segregation says that each parent passes only one allele for each trait. His law of independent assortment says that alleles for different traits are distributed independently of each other. That law is demonstrated in a dihybrid cross.

Question 2

multiple allelism

Answer 2

When over three phenotypes are possible there must be than two alleles. Blood types have three alleles: Ia and Ib are codominant and i is recessive. An AB blood type is codominance. In discontinuous variation traits are mutually exclusive. An example of additive alleles is skin colour

Question 3

Sex linked traits

Answer 3

The female can make only X gametes but the male can make X and Y gametes, so The male determines the sex of the child. Many genetic disorders are sex linked, and most are recessive traits linked to the X chromosome and are expressed in males. Males only need one X linked recessive allele to be affected and females need two, so X linked recessive traits affect more males than females. Very few genes are linked to the Y chromosome. Some X linked recessive disorders are red green colourblindness and hemophilia. The Y is a blank chromosome. Identical twins cant be different sexes.