Thalassemia

Thalassemia It occurs due to an autosomal recessive gene, that expresses in homozygous condition. Two carrier or heterozygous parents can produce an affected child. This genetic defect originated in Mediterranean region due to mutation or deletion in the genes controlling the synthesis of globin chains of Haemoglobin. It also occurs …

PLEIOTROPY

Pleiotropy Pleiotropy is a condition in which single gene affects many characters or single gene affects many phenotypes. It occurs due to inter-relationship between metabolic pathways that contribute to the formation of the different phenotype. Effect of the gene is more evident in one trait and less evident in other …

Polygenic Inheritance

Polygenic Inheritance: Polygenic inheritance is controlled by two or more pairs of nonallelic genes. In which the dominant alleles have a cumulative effect. Each dominant gene added will add to the character and the result will be an additive effect of all dominant genes. These genes are Polygenes and such type of …

Sex Linked Inheritance

Sex-Linked Inheritance: T H Morgan while working on eye color in Drosophila, found that the gene for eye color did not follow the Mendelian pattern of Inheritance. This was due to the gene being present on the X-chromosome. Genes present on the X-chromosome are known as Sex-linked genes, the characters …

DNA structure

 DNA A polymer of deoxyribonucleotides. Length is defined as the number of nucleotides or nucleotide pairs present. This is the characteristic of an organism. Bacteriophage Ø x174 has 5386 nucleotides. Bacteriophage λ has 48502 base pairs. Escherichia coli has 4.6 x 106 base pairs. The haploid genome of human DNA …

DNA Fingerprinting

DNA fingerprinting DNA fingerprinting is a technique to identify an individual by looking at unique patterns in their DNA.  In human’s 99.9%  of the base sequences of DNA are same & are referred as Bulk genomic DNA. The difference lies in remaining 0.1%. It is these differences which make every individual unique …

Regulation of gene expression

Regulation of gene expression It is the metabolic, physiological or environmental conditions that regulate the expression of genes. Housekeeping or constitutive genes: genes whose products are continuously required by the cell hence they continuously transcribe and translate. Non-constitutive genes: genes whose products are not continuously required by the cell & if they …