Final answer:
The inheritance patterns include autosomal recessive, where both parents must carry the allele for a trait to be expressed in offspring; autosomal dominant, where only one allele is necessary for trait expression; and X-linked traits, which depend on the sex chromosome the allele is on. Male offspring will always express a recessive X-linked trait, while females need two copies of the recessive allele. X-linked dominant traits will be passed from an affected parent to the offspring depending on the parent's gender.
Step-by-step explanation:
The inheritance patterns for genetic traits can be determined by their behavior in the genetic crosses. Autosomal recessive traits, like those described in Figure 28.27, require two copies of the mutant gene for the disorder to be expressed. This means that if both parents are carriers, there's a 25% chance for each child to be affected, a 50% chance for them to be carriers, and a 25% chance to not carry the gene at all, reflecting a 3:1 ratio among offspring.
For an autosomal dominant trait, an individual only needs one copy of the allele to show the trait. Dominant traits tend to show in every generation. Individuals with one dominant and one recessive allele are heterozygous and will show the same phenotype as those who are homozygous dominant.
X-linked traits are associated with the X-chromosome. Since males (XY) have only one X chromosome, any recessive X-linked allele will be expressed, as there is no corresponding allele on the Y chromosome to counteract it. In females (XX), a recessive X-linked allele will be expressed only if both X chromosomes carry the recessive allele.
An example of an X-linked recessive trait is colorblindness. With X-linked dominant traits, if a female carrier (XX) has the mutation, she has a 50% chance of passing it to her offspring, whereas the affected male (XY) will transmit the trait to all of his daughters and none of his sons.