What are the 3 methods of genetic recombination?

Why is it more efficient to perform a test cross with a homozygous recessive donor than a homozygous dominant donor? How could the same information still he found with a homozygous dominant donor?

SCIENCE, TECHNOLOGY, AND SOCIETY Imagine that you are a genetic counselor. What advice or suggestions might you give in the following situations? (a) A couple has come for advice because the woman had a sister who died of Tay-Sachs disease. (b) A young man and woman who are not related are engaged to be married. However, they have learned that the mans parents are first cousins, and they are worried about the possibility of increased risk of genetic defects in their own children. (c) A young womans paternal uncle (her fathers brother) has hemophilia A. Her father is free of the disease, and there has never been a case of hemophilia A in her mothers family. Should she be concerned about the possibility of hemophilia A in her own children? (d) A 20-year-old man is seeking counseling because his father was recently diagnosed with Huntingtons disease. (e) A 45-year-old woman has just been diagnosed with Huntingtons disease. She says she will not tell her college-age sons because of the burden it will place on them. Given that the woman, not her sons, is your client, do you have a duty to inform the sons? Explain your reasoning.

Which of the following codes describes position 12 on the long arm of chromosome 13? 13p12 13q12 12p13 12q13