When in meiosis does Robertsonian translocation occur?

When in meiosis does Robertsonian translocation occur?

Robertsonian translocations occur between two acrocentric chromosomes, which are chromosomes in which the centromere is close to one end of the chromosome, resulting in a small (p for petit) length of genetic material beyond the centromere.

How does translocation occur during meiosis?

Translocations occur when chromosomes become broken during meiosis and the resulting fragment becomes joined to another chromosome. Reciprocal translocations: In a balanced reciprocal translocation (Fig. 2.3), genetic material is exchanged between two chromosomes with no apparent loss.

What does Robertsonian translocation do?

Robertsonian translocations involve the long arms of DNA chains fusing together. As cells multiply, this DNA error is copied over and over, and usually the short arms of the DNA chain are lost. The lost information can result in your DNA appearing one full chromosome short of the normal count of 46.

Which of the following combinations of Robertsonian translocation is most common?

The most common Robertsonian translocation is between chromosomes 13 and 14.

How do Robertsonian translocation occur?

A Robertsonian translocation results when the long arms of two acrocentric chromosomes fuse at the centromere and the two short arms are lost. If, for example, the long arms of chromosomes 13 and 14 fuse, no significant genetic material is lost—and the person is completely normal in spite of the translocation.

Is Robertsonian translocation reciprocal?

There are two main types of translocations: reciprocal and Robertsonian. In a reciprocal translocation, two different chromosomes have exchanged segments with each other. In a Robertsonian translocation, an entire chromosome attaches to another at the centromere.

Is Robertsonian translocation balanced?

In balanced form, a Robertsonian translocation takes the place of two acrocentric chromosomes and results in no problems for the person carrying it. But in unbalanced form, Robertsonian translocations produce chromosome imbalance and cause syndrome of multiple malformations and mental retardation.

Is Robertsonian translocation balanced or unbalanced?

The Robertsonian translocation is unbalanced and the baby has three copies of the long arm of chromosome 21 instead of two. This causes a type of Down’s syndrome called translocation Down’s syndrome.

What is a Robertsonian translocation?

Robertsonian translocations Robertsonian translocation is an unusual type of chromosome rearrangement caused by two particular chromosomes joining together. Out of every 1,000 newborn babies, one has a Robertsonian translocation. The phrase Robertsonian translocation is too long for normal conversation and many people shorten it to rob.

What is genotype counseling for chromosomal translocation?

Genetic counseling and genetic testing is offered to families that may be carriers of chromosomal translocations. Rarely, the same translocation may be present homozygously if heterozygous parents with the same Robertsonian translocation have children. The result may be viable offspring with 44 chromosomes.

What percentage of gametes are translocation carriers?

Translocations. If the chromosomes segregate in such a way as to keep the two normal chromosomes together and the two translocation chromosomes together, the resulting gametes are either karyotypically normal or balanced. Of normal offspring, 50% will be karyotypically normal and 50% will be translocation carriers.

Which chromosomes are involved in translocation of chromosomes?

This type of translocation involves only chromosomes 13, 14, 15, 21 and 22, because the ends of their short arms have similar repetitive DNA sequences that predispose to their fusion.