Inheritance Patterns in Pedigree Analysis

The video tutorial explains how to analyze a pedigree chart by testing different modes of inheritance: X-linked dominant, X-linked recessive, autosomal dominant, and autosomal recessive. Each hypothesis is tested against the pedigree to determine which mode of inheritance is possible. The process of elimination shows that the trait in question is autosomal recessive.

What is a common mistake people make when analyzing pedigrees?

• Ignoring the gender of individuals

• Assuming all traits are autosomal recessive

• Focusing only on the dominant traits

• Trying to solve the pedigree all at once

Why was the X-linked dominant hypothesis ruled out?

• The trait appeared in females only

• A son inherited a trait that couldn't be passed by his mother

• The trait skipped generations

• The trait was only present in males

What was the key issue with the X-linked recessive hypothesis?

• The trait was present in all generations

• The trait was only present in females

• The trait was not present in any males

• A male had a dominant trait that couldn't be inherited from his mother

In the autosomal dominant hypothesis, why was it impossible for a certain individual to have the dominant trait?

• Both parents were homozygous recessive

• The individual was male

• The individual was female

• The trait was not present in the previous generation

What conclusion was reached about the mode of inheritance for the trait?

• X-linked recessive

• X-linked dominant

• Autosomal recessive

• Autosomal dominant