Question

The Y-chromosome can be used to trace a person's lineage many generations into the past. What characteristic of the Y-chromosome allows this to be accomplished ?

• A. The Y-chromosome is extremely large.
• B. The Y-chromosome engages in only a tiny bit of crossing over.
• C. The Y-chromosome is carried exclusively in females.
• D. All sperm cells carry the Y-chromosome.

Answer 1

The correct option is B The Y-chromosome engages in only a tiny bit of crossing over.

The crossing over is the phenomenon which occurs between two homologous chromosomes. The X and Y chromosomes are the sex chromosomes which are not homologous to each other since there are different sets of genes on each chromosome. The Y chromosome is involved in the crossing over only to a small extent and so they can be used for studying the lineages. This chromosome is passed only to males from the ancestral male which allows easy study of the past.

Thus, the correct answer is option B.