What is a translocation?
in biology, translocation refers to two completely different processes. In the botany or in the studio of plants, translocation is the movement of material from one place to another in the plant. In genetics, it is an exchange of parts between two chromosomes. In this article we will specifically look at chromosomal translocation. All body cells, with the exception of reproductive cells, have adequate pairs of chromosomes or homologous chromosomes. In homologous chromosomes, both chromosomes are the same size and shape and have the same genes in the same place. One of each pair comes from the mother and one of the father. Within reproductive cells or sex cells, only one copy of each chromosome occurs.
Translocation is a form of structural change that occurs among non -homological chromosomes. It often occurs during meiosis when chromosomes are close to each other. During the translocation, some of the non -homologous chromosomes break away from the original and then are confused. The translocation result is that the structure of both chromeOzoms have now been changed.
different chromosomes carry the same genes in the same place, so different genes are confused during the translocation. Translocations do not affect the number of genes in the cell because no parts of the chromosome are lost. They can affect how genes are expressed by cell because gene sequences change. Since translocation does not cause the loss of genes in the cell, it rarely affects the somatic cell, the non -productive cell.
translocations affect the formation of gametes or sex cells. During meiosis, the homologous pairs of chromosomes are sorted and separated to form gaming cells with only one copy of each chromosome. If one pair chromosome has undergone translocation, it may not be able to pair with their partner to change size or shape. This can actually block meiosis completely, which stops the formation of sex cells.
If meiosis continues, there will be non -homologous chromosomes that have exchangedgenes, grouped only half the time. If they do not do so, game games will have either duplicate genes or genes will be missing. Duplicate and missing genes occur when the right chromosome is segregated with the other chromosome bearing a translocked gene, so there will be two copies of one gene and no copies of the other that have been turned off.
If fertilization occurs in any of these types of gametes, the resulting zygota may not be viable or die. If the Zygota survives and is missing one copy of the gene, this can lead to harmful recessive genes expressed cells. With a normal zygota made of two normal herbuňka te, these recessive genes are usually masked by dominant, so they are not expressed by organism.
Translocations are most often caused by X -ray damage to chromosomes in the cell. Damage causes bonds inside the chromosomes are weaker, which makes them more susceptible to breaking. Breaks lead to many different types of chromosome mutations, including translocations. NoWhich common human diseases caused by translocation are cancer, infertility and Down syndrome.