Answer to Question 1
ANS: B
In X-linked recessive disorders, the affected individuals are usually male. With recessive traits, usually two copies of the gene are needed to produce the effect. Because the male only has one X chromosome, the effect is visible with only one copy of the gene. Females are usually only carriers of X-linked recessive disorders. The X chromosome that does not have the recessive gene will produce the normal protein, so the woman will not show evidence of the disorder. The transmission is from mother to son. Usually the mother and father are unaffected.
Answer to Question 2
ANS: B
LOA is the desired fetal position for the birthing process. Positioning the patient on her left side will accomplish two objectives: (1) by the use of gravity, the fetus will most likely stay in the LOA position; and (2) increase perfusion of the placenta and increase oxygen to the fetus. Positioning the patient on her back decreases placental perfusion. Positioning on her right may facilitate internal rotation and move the fetus out of the LOA position. The hands and knees position is reserved to decrease cord compression, facilitate the fetus out of a posterior position, or increase oxygenation in the presence of hypoxia. Because none of these conditions are present, there is no need to implement this position.
A pedigree for a rare autosomal recessive trait. In these pedigrees, most affected individuals have
A common autosomal recessive allele can produce a pedigree that looks like an autosomal dominant tra
Plot of the percentage of X-linked recessive mutations
Frequency of Heterozygotes for Some Recessive Traits in Several Populations
Nucleosome inheritance after DNA replication
X-linked dominant congenital generalized hypertrichosis (CGH) in a family