Notes on lesson on Genetics |



Gene Expression In Eukaryotes

The genome of higher eukaryotes is very complex. The eukaryotic genome contains DNA many times as compared to the prokaryotic genome. There is various significance of gene regulation.

Interalleic Gene Interaction

Gene interaction is the influence of allelic or non-allelic genes on normal phenotypic expression of the trait. It is of types.

Intergenic Gene Interaction

The gene interaction in which the gene present in one gene locus interacts with the another gene present in another gene locus of the same or different chromosomes for the expression of phenotypic character is called intergenic or non-allelic gene interaction.

Lethal genes Or Pleiotropic genes

The phenomenon in which a single gene has multiple effects is called pleiotropy. This means a single gene often influences more than one phenotypic characters. The gene having multiple phenotypic effects because of its ability to control the expression of a number of characters is called pleiotropic genes.

Sex Linked Inheritance in Drosophila

The inheritance of characters linked to a particular sex is called sex-linked inheritance. Sex-linked inheritance is criss-cross patterns of inheritance. Criss-cross patterns of inheritance is a process of inheritance of traits from a parent to the grandchild [F2] of same-sex through the offspring [F1] of opposite sex i:e father passes his traits to his grandson through his daughter OR mother transfer traits to her granddaughters through her son.

Sex Linked Inheritance in Human Beings

In humans, about 120 sex-linked genetic disorders are found. These are classified as X-linked, Y-linked, and X-Y-linked trits. The common sex-linked disorders that are mostly found in humans are mostly recessive - Color-blindness and Haemophilia.