Types Of Gene

Gene

The functional unit of DNA is gene, the term gene is coined by Wilhelm Johannsen.

Types of gene :-

Based on traits

A. Major gene

Gene that governs qualitative traits, and it is a monogenic gene.

B. Minor gene

Gene that governs quantitative traits, and it is a polygenic gene.

Based on location

A. Nuclear genes

Gene that is found in the nuclear genome in the chromosome.

B. Plasma gene

Gene that is found in the cytoplasm in mitochondria and chromoplast.

Based on position on chromosome

A. Normal gene

Fixed position on chromosome

B. Jumping gene

When one gene is changing their position. Ex- Maize (Because of transposons)

Based on sex linkage

A. Sex linkage gene

Sex-linked traits are characteristics determined by genes located on sex chromosomes, such as the X or Y chromosomes in humans. Ex- colour blindness, Hemophilia

B. Sex limited gene

A character that is present in male or female. Ex- Beared, Milk production

C. Sex influenced gene

A character that is present in male and female but its interface is not the same. Ex- Baldness

Based on lethal effect

A. Lethal gene

Lethal alleles are alleles that cause the death of the organism that carries them

B. Semi-lethal gene

Gene that causes mortality of >50%

C. Sub-vital gene

Gene that causes mortality of <50%

D. Vital gene

Gene that don’t have lethal effect is called vital gene

Base on nucleotide gene

A. Normal gene

The term "normal gene" can refer to the average gene. The average gene is a sequence of nucleotides that contains about 3,000 bases. The human genome contains around 30,000 genes and 3.1 billion base pairs.

B. Split gene

Gene that interrupted sequence of nucleotide are referred to as split gene

C. Pseudo gene

Pseudogenes are nonfunctional segments of DNA that resemble functional genes

Based on mutation

A. Mutable gene

Gene which exhibits the ability to mutate. Ex- Drosophila eye, Human finger

B. Mutator gene

Gene which enhances the natural mutation rate of other genes in the same genome. Ex- Dotted gene in maize

C. Anti-mutator gene

Gene which decreases the natural mutation rate of other genes in the same genome.

Based on epistasis

A. Epistatic gene

Gene whose expression interferes with or masks the effect of other genes are said to be epistatic gene(Affected gene)

B. Hypostatic gene

Genes whose expression is affected (Blocked or Masked) are hypostatic genes.

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