There is a 50% probability that the child will be a boy. If this is the case, he will inherit the X chromosome from his mother and the Y chromosome from his father. Since the woman has DMD, the boy will certainly inherit the disease, since he only has one X chromosome and it carries the disease. We know that both of the mother's X chromosomes carry the disease because since it is recessive, both of her chromosomes must have it in order for her to have it.
There is also a 50% probability that the child is girl. If this is the case, she will inherit a normal X chromosome from her father and the disease-carrying X chromosome from her mother. Since the disease is recessive, she will not be affected by the disease, since she has one healthy X chromosome and one disease-carrying one.
If the child is a girl, there is a 0% chance that she will have the disease (although she will be a carrier).
If the child is a boy, there is a 100% chance that he will inherit the disease.
The answer is D)
Which of the following organisms is not nekton? a. Whales
b. Crabs (answer)
c. Sharks
d. Dolphins
It should be carbohydrates
The sun appears to cross the plane of Earth's equator
when it reaches either one of the "equinox" points in the sky.
Answer:
Two gametes end up with 30 chromosomes, one gamete will have 31 and one will have 29.
Explanation:
During meiosis, a single diploid cell divides into four haploid cells with half the chromosome number than the parent cell.
During meiosis I, homologous chromosomes separate and the chromosome number in the two daughter cells goes down by half. During meiosis II, the "sister" chromatids separate, and the chromosome number in the respective daughter cells remains the same.
Non-disjunction of a single dyad in meiosis II causes that one of the daughter cells will have an extra chromosome, and another will be lacking one. The two other gametes will be normal.
I drew a simple example of what would happen during meiosis of a 2n=4 cell if there was non-disjunction in a single dyad during meiosis II.
