Question

inquizitive: chapter 8: chromosomes and human genetics: curing the incurable
normal female
normal male
unaffected male
female introducing gene into family
correct answer(s)
autosomal recessive
autosomal dominant
sex - linked
incorrect answer(s)

Explanation:

1. In autosomal - recessive inheritance, two copies of the recessive allele are needed to show the trait. If the trait skips generations, it can be autosomal - recessive. Here, the trait seems to skip generation II.
2. In autosomal - dominant inheritance, only one copy of the dominant allele is needed to show the trait. If the trait appears in every generation, it can be autosomal - dominant. But here, it doesn't appear in every generation.
3. In sex - linked inheritance, traits are carried on the sex chromosomes. If it's X - linked recessive, more males are usually affected. If it's X - linked dominant, affected males pass the trait to all their daughters. Since only males are affected in generation III and there is no clear pattern of sex - linked inheritance (like criss - cross inheritance), it is less likely to be sex - linked.

Answer:

autosomal recessive