What Is Mutation And What Kinds Of Diseases Caused By Mutation?

Mutation can be defined as a permanent change in cell's DNA. The changes in the DNA are reflected by the change expression of the character. If these changes occur in somatic cell, their impact is limited to the affected organism's life. However, any change in the mutation in the germ line-cell may become hereditary.
Kinds of mutation: there are two kinds of mutation.
Chromosomal Aberration:
These are mega or big changes, which involve:
Presence of an extra chromosome.
Loss of chromosome from the genome.
Deletion i.e. removal of one or a few bases from DNA.
Insertion i.e. addition of one or few base in DNA.
Inversion i.e. inverted reunion of the middle segment after breakage of a chromosome at two points, resulting in a change in sequence of genes or nucleotides.
Such mega changes leads to Down's syndrome etc.
Point mutation: these are alteration of one or few base pairs in the coding sequence of the chromosome. Such mutations occur by:
Spontaneous pairing error during DNA replication.
Damage to the DNA caused by mutagens, usually radiations and chemicals. Point mutation are the cause of sickle cell anaemia, phenylalanine.
Disease caused by point mutations:
Sickle cell anaemia: it is due to a change of amino acid glutamic acid by valine at position from N terminal end in haemoglobin beta chain. It reduces the ability to carry oxygen.
Phenylketonuria: in this disease, phenylketonuria is not degraded because of defective enzyme phenylalanine hydroxylate. Phenylalanine consequently accumulates in the cells leading to mental retardation, as the brain fails to develop at the infant stage.

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Mutation can be defined in terms of biology as an organism that has the characteristics; which emerges by some kind of alterations in chromosomes.

And in terms of genetics it can be defined as, any process that alters the structure of gene and in that nucleic acid sequence which is inherited.

Mutation can be divided into following categories.
1. the single base substitutions
2. the insertions and deletions
3. and the chromosomal mutations.

Mutation can also become the reason of many different types of genetic disorders
A mutation is actually a permanent change in the gene DNA sequence . Mutations in a DNA of a gene sequence can simply alter the amino acid sequence of protein encoded by the gene. But what a question is there now is that how does this happen? It's just like words in a sentence, the DNA sequence of each gene determines the amino acid sequence for the protein it encodes. The DNA sequence is actually interpreted in the groups of three nucleotide bases, called the codons.

Each codon (A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid) specifies a single amino acid in a protein.

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