Question

chapter 8: chromosomes and human genetics: curing the incurable
page(s) 155 - 162
8.5. compare and contrast the inheritance of recessive, dominant, and sex - linked genetic disorders.
complete the passage regarding inheritance of genetic conditions in humans.
complete the passage by filling in the blank(s). drag the word(s) below to fill in the blank(s) or use your keyboard to choose word(s) from the dropdown menus.
analyzing the pattern of inheritance for a genetic condition can help determine the mode of inheritance. if a genetic condition is not present in either parent but is sometimes inherited by their offspring, the condition is likely. if a genetic condition is not present in either parent, it is never inherited by their offspring. but when either parent is affected by the condition, their offspring have at least a 50% chance of inheriting it and the condition is likely. if a genetic condition is more readily expressed by male offspring than female offspring, the condition is likely.
sex - linkedautosomal dominantautosomal recessive*

Explanation:

• Autosomal recessive: For an autosomal recessive condition, two copies of the recessive allele (one from each parent) are needed for the trait to be expressed. If neither parent shows the trait (they are carriers, i.e., heterozygous), there is a chance (25% in a typical Punnett - square analysis for two heterozygous parents) that their offspring can inherit two recessive alleles.
• Autosomal dominant: In an autosomal dominant condition, only one copy of the dominant allele is needed for the trait to be expressed. If a parent has the autosomal dominant condition (heterozygous or homozygous dominant), there is at least a 50% chance (if the parent is heterozygous) that the offspring will inherit the dominant allele.
• Sex - linked: Sex - linked (usually X - linked) conditions are more common in males. Males have one X and one Y chromosome. If a recessive allele is on the X chromosome, males only need one copy of that recessive allele (since they don't have a second X to potentially mask it) to show the trait. Females have two X chromosomes, so they need two copies of the recessive allele (in the case of recessive X - linked traits) to show the trait.

Answer:

1. autosomal recessive
2. autosomal dominant
3. sex - linked