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Single-gene inheritance - Human pedigree analysis

4 important questions on Single-gene inheritance - Human pedigree analysis

How is a autosmal recessive disorder revealed?

By the appearance of the disorder in the male and female progeny of unaffected parents.

How can you recognise a autosomal dominant disorder?

Autosominal dominant disorders show affected females and males in each generation; they also show affected men and woman transmitting the condition to equal proportions of their sons and daughters.

How are X-linked recessive disorder recognised?

Many more male than females show the rare phenotype.
None of the offspring of an affected male show the phenotype but all his daughters are carriers. In the next generation half the sons of these females show the phenotype.
None of the sons of an affected male show the phenotype, nor are they carriers.

How are X-linked dominant disorders recognised?

Affected males pass the condition to all their daughters but not their sons.
Affected heterozygous females mating with unaffected males pass the condition to half their sons and daughters.

The question on the page originate from the summary of the following study material:

An Introduction to Genetic Analysis | 9781319114770 | Anthony J F Griffiths, et al

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