Achondroplasia is a form of dwarfism inherited as a completely dominant trait. Two achondroplastic dwarfs have a dwarf child; la
ter, they have a second child who is normal. What are the genotypes of the two parents in this mating? What is the probability that their next child will be normal? A dwarf?
There's 25% probability that their next child will be normal, and 75% of it being a dwarf.
Explanation:
Achondroplasia (A) is a dominant trait.
Two achondroplastic dwarfs (A_ x A_) have a dwarf child (A_) and a normal child (aa). The second child must be aa because if it had a dominant allele it would also be dwarf.
The only way for two achondroplastic parents to have a normal child is that <u>they are both heterozygous (Aa) for this gene.</u>
The cross Aa x Aa would produce the following offspring probabilities:
1/4 AA - dwarf
2/4 Aa - dwarf
1/4 aa - normal
So there's 1/4=25% probability that their next child will be normal, and 3/4=75% of it being a dwarf.
At the start of a drought, groundwater may not be noticeably lower (not B). Only aquifers near the ocean may become contaminated with salt water (not C). And it is definitely not D.
The observation from the first question would tend to disprove the idea that evolution is based on b. inheritance of acquired characteristics because according to the experiment <span>theory of <span>adaptation was taken as a basis. The answer for the next question is definitely adaptation as at first every live -being should get used to its environment in order to develop and so on.</span></span>
