Derivative chromosome

Derivative Chromosome

A schematic representation of a derivative chromosome

A derivative chromosome is a type of chromosome that has undergone structural rearrangements, resulting in changes to its genetic material. These rearrangements can occur through various mechanisms, such as translocations, inversions, deletions, or duplications. Derivative chromosomes can be found in both plants and animals, and they play a significant role in genetic diversity and evolution.

Types of Derivative Chromosomes

There are several types of derivative chromosomes, each characterized by specific structural changes:

1. Translocation Derivative Chromosome: In this type, a segment of one chromosome breaks off and attaches to a non-homologous chromosome. This can result in the exchange of genetic material between the two chromosomes, leading to the formation of a derivative chromosome.

2. Inversion Derivative Chromosome: Inversions occur when a segment of a chromosome breaks off, flips, and reattaches in the reverse orientation. If this inverted segment then becomes involved in a translocation event, it can give rise to an inversion derivative chromosome.

3. Deletion Derivative Chromosome: Deletions involve the loss of a segment of a chromosome. If the remaining ends of the broken chromosome fuse with another chromosome, a derivative chromosome with deleted genetic material can be formed.

4. Duplication Derivative Chromosome: Duplications occur when a segment of a chromosome is copied and inserted into another chromosome. This can result in the formation of a derivative chromosome with duplicated genetic material.

Significance and Implications

Derivative chromosomes have important implications for genetic diversity and evolution. They can lead to the creation of new genetic combinations, which can be advantageous or detrimental to an organism's survival and reproductive success. Some derivative chromosomes may confer adaptive traits, allowing individuals carrying them to better adapt to their environment. On the other hand, derivative chromosomes can also disrupt normal gene function, leading to genetic disorders or reduced fertility.

Furthermore, derivative chromosomes can play a role in speciation. When individuals with derivative chromosomes mate with individuals carrying the normal complement of chromosomes, reproductive barriers can arise due to differences in chromosome structure or gene content. Over time, these reproductive barriers can contribute to the formation of new species.

Examples

One well-known example of a derivative chromosome is the Philadelphia chromosome, which is associated with chronic myeloid leukemia (CML). The Philadelphia chromosome is formed through a reciprocal translocation between chromosomes 9 and 22. This translocation results in the fusion of the BCR (breakpoint cluster region) gene on chromosome 22 with the ABL1 (Abelson tyrosine-protein kinase 1) gene on chromosome 9. The resulting fusion gene produces a protein with abnormal tyrosine kinase activity, leading to uncontrolled cell growth and the development of CML.

See Also

• Chromosome
• Genetic Diversity
• Evolution
• Translocation
• Inversion
• Deletion
• Duplication
• Speciation
• Philadelphia Chromosome
• Chronic Myeloid Leukemia