Modes of Inheritance in Pedigrees

The video tutorial introduces an algorithm to solve pedigree questions, focusing on determining the mode of inheritance. It explains how to identify recessive and dominant conditions by examining the parents and offspring in a pedigree. The tutorial provides a step-by-step guide to distinguish between autosomal and X-linked conditions, emphasizing the importance of male-to-male transmission in identifying X-linked traits. The video concludes with practice questions to reinforce the algorithm's application, aiming to help viewers quickly and accurately solve pedigree questions.

What is the first step in determining the mode of inheritance in a pedigree question?

• Look for male-to-male transmission.

• Identify the gender of the offspring.

• Determine if the parents are affected.

• Check if the offspring are affected.

If both parents are unaffected, what can be inferred about the condition?

• It is a recessive condition.

• It is a dominant condition.

• It is an X-linked condition.

• It is a mitochondrial condition.

How can you determine if a recessive condition is autosomal or X-linked?

• By checking if the condition affects only offspring of affected parents.

• By checking if the condition affects both males and females.

• By checking if the condition affects only females.

• By checking if the condition affects only males.

What indicates an X-linked recessive condition in a pedigree?

• There is male-to-male transmission.

• Only males are affected.

• Both males and females are affected.

• Only females are affected.

What is a key indicator of an autosomal dominant condition?

• Presence of male-to-male transmission.

• Absence of male-to-male transmission.

• Only females are affected.

• Only males are affected.

What does the absence of male-to-male transmission suggest in a dominant condition?

• The condition is mitochondrial.

• The condition is X-linked.

• The condition is autosomal.

• The condition is recessive.

In a pedigree, if only males are affected and the parents are unaffected, what is the likely mode of inheritance?

• Autosomal dominant

• X-linked recessive

• Mitochondrial

• Autosomal recessive

What is the mode of inheritance if both males and females are affected and the parents are unaffected?

• Autosomal dominant

• X-linked recessive

• Autosomal recessive

• Mitochondrial

Which genetic disorder is typically autosomal recessive?

• Huntington disease

• Leber hereditary optic neuropathy

• Classic galactosemia

• Hemophilia B

Which condition is associated with a structural defect and is autosomal dominant?

• Leber hereditary optic neuropathy

• Classic galactosemia

• Hemophilia B

• Huntington disease