The mutation will occur on the X chromosome. Males are more susceptible to sickle cell amenia because they only carry one X chromosome instead of two when compared to a set of female chromosomes. If a female only has the mutation on one chromosome the disease will not appear. However, when a male recieves the mutation on the X chromosome, the disease would appear, because they only have one X chromosome.
Answer and Explanation:
Nondisjunction occurs when homologous chromosomes fail to segregate during anaphase I or sister chromatids fail to segregate during anaphase II. The result is an addition or loss of one or more chromosomes. Nondisjunction is associated with disorders like Down's syndrome due to an extra chromosome, Klinefelter's syndrome or Turner's syndrome. These phenomenon where one has three members of homologous chromosome is called trisomy.
interphase, telophase, and cytokinesis
Answer:
- If they have one child, the probability that he or she will be affected is 1/4.
- If they have two children, the probability that at least one of them will be affected is 7/16.
Explanation:
A cross between two heterozygous Aa individuals will produce the followinf offspring: 1/4 AA, 2/4 Aa and 1/4 aa.
Since the disease is recessive, 1/4 of the offspring will have the <em>aa </em>genotype and 3/4 of the offspring will be unaffected.
Every time they have children new gametes were generated <u>independently</u>.
The probability of having <u>no</u> affected children both times is, according to rules of probability for independent events, 3/4 × 3/4 = 9/16 (it's the probability of having a healthy child the first time multiplied by the probability of having a healthy child the second time).
The probability of having at least one affected child is 1 - probability of no affected children = 1 - 9/16 = 7/16.
