Heredity Test - 1

Genetics, a term coined by Bateson (1906), is the study of heredity and variations. Genetics is the study of genes, heredity, and genetic variation in living organisms.

Gregor Mendel is known as the father of genetics.

A cross between hybrid and either parent is called back cross. It is used in horticulture, animal breeding and in production of gene knockout organisms.

Mendel failed to produce the same results in plants like hieracium (Hawk weed) and bean (Phaseolus).

Escherichia coli (K12 strain, an inhabitant of intestine) is widely used in genetic research because it is easy to culture in laboratory.

Independent assortment of genes and their corresponding traits was first observed by Gregor Mendel in 1865 during his studies of genetics in pea plants. He was performing dihybrid crosses, which are crosses between organisms that differ with regard to two traits. He discovered that the combinations of traits in the offspring of his crosses did not always match the combinations of traits in the parental organisms. Thus, Law of Independent Assortment is formulated.

From a cross AABb × aaBb, the genotypes AaBB : AaBb : Aabb : aabb are obtained in the ratio 1 : 2 : 1 : 0.

If the frequency of a dominant phenotype in a stable population is 75%, then the frequency of recessive allele will be 25%.

Aabb x Aabb gives 3 : 1 phenotypic ratio as Aa and bb will be the gametes and offspring will have genetic constitution of AAaa, Aabb, Aabb and bbbb.

Alternative forms of the gene are called alleles. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent.