Final answer:
In an individual heterozygous for a reciprocal translocation, both adjacent-1 segregation and adjacent-2 segregation result in nonviable gametes.
Step-by-step explanation:
In an individual heterozygous for a reciprocal translocation, both adjacent-1 segregation and adjacent-2 segregation result in nonviable gametes.
Adjacent-1 segregation occurs when chromosomes segregate in a way that one gamete receives a normal set of chromosomes and the other gamete receives both translocated chromosomes. This results in nonviable gametes.
Adjacent-2 segregation occurs when chromosomes segregate in a way that one gamete receives both normal chromosomes and the other gamete receives both translocated chromosomes. Again, this results in nonviable gametes.