Suppose you examined a pedigree of a large family, going back 6 generations. In generation 5, a woman ("G5W") has a serious gene
tic disease--its first incidence in the family. In the next generation, three of her offspring--two boys and one girl--are affected, with one daughter unaffected. What is the most likely explanation?(A) G5W's parent--the one who married into the family--carried the disease allele (but wasn't affected), and it is autosomal dominant.(B) A mutation in one of the G5W's parents, during gamete formation, created an X-linked dominant disease allele.(C) A mutation in G5W created an autosomal dominant disease allele.(D) The disease allele is recessive and X-linked; G5W's spouse also has the allele.
B: A mutation in one of G5W's parents, during gamete formation, created an X-linked dominant disease allele.
You need to analyze the sex gametes.
Boys are XY
Girls are XX
If you have an X-linked dominant disease you need only one affected X gamete to have the disease.
The mother has XX' where X' is de affected and reproduce with a healthy man XY and breed unhealthy boys, but because of the heterozygous gametes you could also have healthy ones XX and XY
They contain symbiotic bacteria called rhizobia within nodules in their root systems, producing nitrogen compounds that help the plant to grow and compete with other plants. When the plant dies, the fixed nitrogen is released, making it available to other plants; this helps to fertilize the soil.
Answer: Sea snakes have many adaptations. Like for instance, they have paddle-like tails to help swim more efficiently, and a special flap of tissue to prevent water from entering its lungs.
Explanation:
They develop these adaptations for survival purposes.
