What is the difference between a gene mutation and a chromosomal mutation

A mutation is a permanent alteration of the nucleotide sequence of a gene. Gene mutations and chromosomal mutations mainly differ in the magnitude of the alteration.

The main difference between gene mutation and chromosomal mutation is that gene mutation is an alteration of the nucleotide sequence of a gene whereas chromosomal mutation is an alteration of the structure or number of chromosomes.

Mutations are caused by errors in DNA replication , homologous chromosome segregation or mutagens such as UV and chemicals. They alter the production of functional proteins. The influence of chromosomal mutations is higher than that of gene mutations since the magnitude of mutation in chromosomal mutations is high.

A gene mutation is an alteration of the nucleotide sequence of a gene. Gene mutations can be caused by errors in DNA replication during cell division by both mitosis and meiosis.

In addition, gene mutations are caused by environmental factors such as UV and chemicals. These factors are called mutagens. Sickle cell anemia, hemophilia, cystic fibrosis , Huntington syndrome, Tay-Sachs disease, and many cancers are caused by gene mutations. The two types of gene mutations are point mutations and base pair insertions or deletions.

Point mutations are caused by single nucleotide substitutions. Three types of single nucleotide substitutions can be identified as silent mutations, missense mutations, and nonsense mutations. Some single nucleotide alterations can be tolerable since they still produce the same protein due to the degeneracy of the genetic code. This type of a mutation is called silent mutations. Some alterations in the nucleotides may alter the corresponding amino acid.

It causes both structural and numerical alteration in the chromosome. Sometimes a portion of a chromosome, which contains several genes in the DNA strand removes and rejoins inversely to the original position. This is known as an inversion, and it is a type of chromosome mutation. Inversions do not cause the number to change, but different interactions may result as the gene order has been changed. Hence, the phenotypes become different or abnormal.

Deletions may take place due to exposure to radiation, high heat, or viruses. Usually, deletions are results of external causes, and the affected area of the chromosome determines the extent of change or the damage.

All these chromosomal mutations seriously affect the structure and the number of chromosomes in an organism. They lead to the alteration of protein synthesis and gene expression. Prader-Willi Syndrome and Cri-du-chat syndrome are some of the examples of chromosome mutations caused due to deletions.

When alteration of the nucleotide sequence of a gene occurs, it is known as a gene mutation. On the other hand, when the chromosome structure and number change, it is a chromosome mutation. This is the fundamental difference between gene mutation and chromosome mutation. Gene mutation is a small scale mutation which can be point mutation or frameshift mutation.

There are two main groups of chromosome abnormalities — numeric and structural. Numeric abnormalities, as the name suggests, involve the number of chromosomes. Monosomy occurs when one of the two chromosomes is missing from a pair. Trisomy occurs in individuals with an extra chromosome. For example, those with Down syndrome have three copies of chromosome 21 instead of two copies. In addition to chromosome losses or gains, chromosomes can simply be altered, which is known as structural abnormality.

Many structural abnormalities exist. A translocation occurs when a piece of one chromosome breaks off and attaches to another chromosome. Deletions occur when a portion of the chromosome breaks and genetic material is lost or deleted.

A duplication happens when part of a chromosome is copied and additional genetic material is present. When a chromosome has broken, rotated and reattached, an inversion has occurred.

A pericentric inversion occurs in the centromere, and a paracentric inversion occurs in the p or q arms. Isochromosomes are another type structural abnormality in which the chromosome has two identical arms eg, two p arms. A dicentric chromosome is a chromosome with two centromeres, and a ring chromosome is one in which the chromosome breaks in two places and the ends fuse together to form a ring shape.

A gene mutation is a permanent change in the DNA sequence of a gene. Mutations can occur in a single base pair or in a large segment of a chromosome and even span multiple genes. Mutations can result from endogenous occurring during DNA replication or exogenous environmental factors. Supriya Yadav. Jeevan Chandra at asst prof. Unisa Timbo. Sabbathina Tiana. Show More. Views Total views. Actions Shares. No notes for slide. Gene vs.

The dicentric and acentric combinations are similar to those formed after replication of single strands in the same chromosome. Genetic make up Promoter Total views 14, On Slideshare 0. From embeds 0. Number of embeds 6.