Genetics

The resemblance between the child and its parents lead us to a new topic of biology called Genetics. We find certain characteristics are seen between the children and grand parents too. The branch of biology that deals with heredity and variation is called genetics.

Heredity: It is the inheritance of characters passed on from parent to offspring is called heredity.

Variation: Differences that exist between the individuals of the same species is called the variation. Even the children of same parents show some differences in their characters.

Gregor Johann Mendel was called the father of genetics. He has done a lot of research work on the plant Pisum sativum (pea plant) and tabulated his results. Now we call his work as Mendel's law of inheritance.

Mendel's work was re discovered by Hugo de vries of Holland, Tsermark of Austria and Karl Correns of Germany. These three biologists worked independently and confirmed Mendel's work.

Gene : A gene is the physical and functional unit of heredity. The word gene was coined by W. Johannsen. Chromosomes: These are the physical carriers of genes.

Genes are arranged in a linear manner at specific positions on specific chromosomes. Thus genes are unit of heredity.

Genes in turn are made up of DNA( Deoxyribose nucleic acid) and some associated proteins. Maps of human genome copy number variation (CNV) are maturing into useful resources for complex disease genetics. Four new studies increase the resolution of CNV maps and seek to locate human phenotypic variation on these maps. Genetic variation ranges in size from the fine scale of SNPs to the multi-kilobase deletions and duplications that comprise copy number variation (CNV), variation in the number of copies of a genomic segment. Since observations in 2004 that human genomes harbor extensive CNV, geneticists have sought to determine what segments of the genome are affected by CNV, to develop effective ways to measure the dosage of these segments in individuals' genomes, and to assess how CNV relates to variation in phenotype.

Thus Genetics is a branch of biology that is fast developing.