Final answer:
The claim that mice with a Rec8 deficiency are useless is false. Rec8 is crucial for chromosomal segregation during meiosis, and while its deficiency may cause infertility, the mice can still be important for research.
Step-by-step explanation:
The statement "Mice with a Rec8 deficiency are rendered useless" is false. Rec8 is a protein that plays a crucial role in meiosis, the process of cell division that produces reproductive cells such as sperm and eggs. While a deficiency in Rec8 can lead to chromosomal segregation errors and result in infertility, it does not render the mice 'useless.' These mice can still be valuable for scientific research, especially for studies related to chromosomal behavior during cell division and the implications of meiotic failure. In mice, a deficiency in Rec8 may result in reproductive problems, such as reduced fertility or impaired embryo development, but it does not render them useless.