Answer:
It seems that a reciprocal translocation is going on.
Explanation:
A translocation occurs when a chromosomal fragment changes its location in the same chromosome from the original to a new one. Or when it leaves the chromosome to re-locate in a new different chromosome.
According to this, there are different types of translocations:
- Intrachromosomal translocations:
- Intra-radial: the change in position occurs in the same arm of the chromosome. For instance, 123.456789 → 123.478569
- Extra-radial: The change in position occurs from one arm to the other of the same chromosome. For instance, 123.456789 → 15623.4789
- Extrachromosomal translocations:
- Transposition: not reciprocal interchange. The fragment leaves a chromosome to re-locate in another chromosome. The other chromosome does not send any fragment to the first one.
- Reciprocal translocation: There is a reciprocal interchange. A fragment of chromosome A goes to B, and a fragment of chromosome B goes to A.
Reciprocal translocations might be:
- Fraternal: the interchange occurs among homologous chromosomes
- External: the interchange occurs among non-homologous chromosomes
Reciprocal translocations are easily recognized during meiosis because an association between four chromosomes can be observed. This association is a quadrivalent structure.
During metaphase 1, the centromeres involved in the quadrivalent originate centromeric co-orientation or disjunction.
