Structure of Cell and Cell Organelles and Their Functions In 1665, an Englishman by the name of Robert Hooke examined thin slices of cork and observed that it was composed of numerous little boxes, fitted together like honey comb. Since these boxes resembled the compartment of monastery he named them as cells. The cork cells […]

Structural Chromosomal Aberrations Structural chromosomal aberrations cause structural abnormalities in chromosome structure. They alter the sequence or the kind of genes present in chromosome. These are further classified into four groups based upon whether they alter the gene sequences, number or location. Changes in the structure of chomosomes. a. Loss or addition of segments of […]

Types of Gene Action The interaction with in alleles of gene controlling a single character may be dominant, incomplete dominance and co-dominance and are called intra allele interaction. When there is a interaction occurs between different pairs of alleles influencing a character of an individual is said to be interallelic interaction or epistatic. The gene […]

RNA And Its Structure, Function and Types With the discovery of the molecular structure of the DNA double helix in 1953, researchers turned to the structure of ribonucleic acid (RNA) as the next critical puzzle to be solved on the road to understanding the molecular basis of life. Ribonucleic acid (RNA) is a type of […]

Numerical Mutations (Polyploidy) Mutations which alter the chromosome structure, size or gene arrangement are chromosomal mutations. Chromosomal mutations are widely called as chromosomal aberrations. These are grouped into two broad classes based open whether they alter the structure or number of chromosomes. Chromosome Mutations – gross changes in chromosomes. Changes in the number of chromosomes. […]

Quantitative Traits – Qualitative Traits Quantitative genetics (Inheritance of multiple Genes) The phenotypic traits of the different organisms may be of two kinds, viz., qualitative and quantitative. The qualitative traits are the classical Mendelian traits of kinds such as form (e.g., round or wrinkle seeds of pea); structure (e.g., horned or hornless condition in cattles); […]

Regulation of Gene Expression Each cell of a living organism contains thousands of genes. But all genes do not function at a time. Genes function according to requirements of the cell. Genes control the phenotypic expression of various characters through the production of specific enzymes. Enzymes are special proteins which catalyse chemical reactions. The production […]

Multiple Factor Hypothesis Multiple factor It is quite natural that small differences exist among individuals of similar genotype due to the effect of environment on genotype. On the other hand, there are some heritable differences also exist with continuous variation. Most of the economical traits show continuous variation and they are measurable or quantifiable. Quantitative […]

Multiple Alleles Allele is a shorter term than allelomorph (another form) is the alternate form of gene. Many genes have two alternate forms but several other have more than two alternate forms. More than two alleles at the same locus give rise to a multiple allelic series. Multiple alleles can be defined as a series […]

Mutations Natures intention is that the exact genetic information from both parents will be seen in the offspring’s DNA in the critical stages of fertilization. However, it is possible for this genetic information to mutate, which in most cases, can result in fatal or negative consequences in the outcome of the new organism. Non-Disjunction and […]