Chromosomal Translocation
The translocation process in chromosomes leads to chromosomal abnormalities. The whole process involves breaking a chromosomal fragment and attaching it to another chromosome. This translocation can be either reciprocal or non-reciprocal. The reciprocal translocation involves the exchange of chromosomal fragments between non-homologous chromosomes. In non-reciprocal, there is no exchange involved. It is a one-way shift of genes from a non-homologous chromosome to another.
Most chromosomal translocations are associated with diseases and infertility.
Chromosomal Cross Over
Crossing over involves the exchange of genetic material between two non-sister chromatids of homologous chromosomes. The product is usually a recombinant chromosome. The point of link between the non-sister chromatids of the homologous chromosomes is called chiasma. The cross-over between non-homologous chromosomes is very rare.
This pairing of homologous chromosomes usually happens during meiosis (prophase â… ). This results in different combinations of gene sets in the recombinant product.
Explore: Chromosomal Abnormalities
Difference between Translocation and Crossing Over
Translocation |
Crossing Over |
|---|---|
| It involves the exchange of chromosomal segments between non-homologous chromosomes. | It involves the exchange between two homologous chromosomes. |
| Translocation can create chromosomal abnormalities. | Crossing over is a general process that happens during meiosis (prophase â… ). |
| It is a type of mutation which alters genetic information. | It produces recombinant chromosomes with different combinations of gene sets. |
| It results in fatal diseases (cancer) and infertility. | It does not create any abnormalities or diseases. |
Also see: Differences between Linkage and Crossing Over
Frequently Asked Questions on Difference between Translocation and Crossing Over
What is Robertsonian translocation?
It is the most common translocation seen in humans. It can involve two homologous/non-homologous chromosomes. Here, the chromosomal break happens in the acrocentric centromere. This results in a recombinant chromosome with a long arm and a very short arm. The long arm has almost all essential genes, while the short arm has non-essential genes. This type of translocation usually causes genetic disorders. Example – Down Syndrome.
What is a synapsis?
Synapsis is the pairing of homologous chromosomes that takes place during meiosis. This synapsis formation is followed by the process of crossing over. Thus, it allows proper segregation of the chromosomes.
What is chiasma?
Chiasma is the physical contact between the non-sister chromatids of the homologous chromosomes. It is a linking point where the exchange of genes can occur. The absence of chiasma formation can also result in improper segregation of the chromosomes.
Also Read: Meiosis â… : The Reduction Cell Division
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