Question

from this reading, what did you find out? what facts did you learn from this? did you already know this? was it interesting to you?

When Mendel proposed that each trait is determined by a pair of genes, it presented a potential problem. If parents pass on both copies of a gene pair, then offspring would end up with four genes for each trait. Mendel deduced that sex cells — sperm and eggs — contain only one parental gene of each pair. The half-sets of genes contributed by sperm and egg restore a whole set of genes in the offspring. Mendel found that different gene combinations from the parents resulted in specific ratios of dominant-to- recessive traits. The results of a cross between two hybrid parents — each carrying one dominant and one recessive gene — were key to his synthesis. For example, a cross between two yellow-seed hybrids produces three times as many yellow seeds as green seeds. This is Mendel's famous 3 to 1 ratio.

Answer 1

George Mendel,conducted hybridization experiments on garden peas and proposed the laws of inheritance in living organisms.Mendel investigated characters in the garden pea plant that were manifested as two opposing traits like tall or dwarf plants,yellow or green seeds.Mendel conducted his experiments in three generations;the P parent generation,(F₁),and (F₂)second filial generation.He examined seven traits of true breeding pea pods,each having two alternate forms for a single trait. When alternate forms of a single trait were crossed,one of the forms disappeared in the F₁generation,then reappeared in the F₂ generation.The form of trait that masks the other traits is called the dominant trait.The dominant and mask traits appear in the F₂ generation in a 3:1 ratio This allowed him to set up a basic frame work of rules governing inheritance ,which was expanded on by later scientists to account for all the diverse natural observations and complexity inherent in them.Mendel's first law of segregation explains the mechanism underlying the inheritance of a single trait as determined by the monohybrid cross.Mendel performed dihybrid crosses to examine the mechanism underlying the inheritance of two traits.He concluded that the alleles for the two different traits segregated independently of one another.He called this phenomenon the law of independent assortment.When expeiments on peas were repeated using other traits in plants.It was found that sometimes the F₁ had a phenotype that do not resemble either of the two parents and was in between two.In a cross between true breeding red flower(RR)and true breeding white flowered plant(rr),the F₁(Rr) was pink.Modern genetics has determined the biochemical basis for dominant and recessive alleles.Dominance involves coding genes that produce proteins.A recessive allele may not produce a protein and may appear to be masked by the dominant allele.