An animal heterozygous for a reciprocal balanced translocation has the following chromosomes:
           MN • OPQRST
           MN • OPQRjkl
           cdef • ghijkl
           cdef • ghiST

Identify the gametes produced by alternate segregation. Which if any of these gametes are viable?

Key Concepts

Heterozygous Reciprocal Balanced Translocation

A heterozygous reciprocal balanced translocation occurs when two non-homologous chromosomes exchange segments, resulting in a rearrangement of genetic material. In this case, one chromosome carries a combination of segments from both original chromosomes, while the other retains the original segments. This can lead to unique gamete combinations during meiosis, affecting genetic diversity and viability.

Meiosis and Gamete Formation

Meiosis is the process of cell division that produces gametes (sperm and eggs) with half the number of chromosomes. During meiosis, homologous chromosomes pair up and can undergo recombination, leading to genetic variation. The way chromosomes segregate during meiosis, particularly in cases of translocations, influences the types of gametes produced and their viability.

Alternate Segregation

Alternate segregation is a specific pattern of chromosome separation during meiosis in organisms with translocations. In this process, chromosomes that are not involved in the translocation segregate together, leading to the formation of viable gametes. This contrasts with adjacent segregation, which often results in unbalanced gametes that are typically non-viable due to an improper distribution of genetic material.