(a) Many patterns of inheritance deviate considerably from the pattern of inheritance as explained by Mendel. List any four such inheritance patterns…

-Incomplete dominance

-Codominance

-Pleiotropy

-Polygenic Inheritance

-linkage

Incomplete Dominance – snapdragon / Antirrhinum sp. / $\displaystyle 4$ O' clock plant / Dog flower / Mirabilis jalapa ,

When F1 hybrid resembles in between two parents

Co-dominance- ABO blood grouping in human beings,

In AB blood group both alleles IA and IB are able to express themselves.

Pleiotropy-One gene controls many character, eg.Phenylketonuria in human beings- in this case single gene mutation causes mental retardation reduction in hair and skin pigmentation.

Polygenic Inheritance -When one trait is controlled by three or more genes, eg skin colour controlled by $\displaystyle 3$ genes( A, B, C). Each type of the allele in the genotype would determine the darkness or lightness of the skin in an individual.

Linkage- Some of the closely linked genes do not follow Mendelian inheritance pattern of independent assortment, eg. Gene for eye colour and body colour in fruitfly did not segregate independently and F2 ratio deviates from $\displaystyle 9$:$\displaystyle 3$:$\displaystyle 3$:1.

By switching the position of promoter and terminator the coding strand

becomes template strand .

-If both strands acts as template, they would code for RNA molecule with

complementary sequences hence would form a dsRNA and prevent translation.

-If both strands acts as template, they would code for RNA molecules with

different sequences and if they code for proteins, they will make different proteins.Hence one segment of DNA would be coding for two different proteins and complicate genetic information transfer machinery.