Genetic Probability and Disorders

The video explains that humans inherit two copies of each gene, one from each parent. Recessive non-working genes are common, but usually compensated by a working gene. Problems arise when both parents carry the same non-working gene, leading to autosomal recessive disorders in children. The example of Anne and John illustrates how genetic inheritance works, with a 1 in 4 chance of their child being affected. Consanguinity, or relationships between relatives, increases the likelihood of genetic disorders due to shared genes.

How many copies of each gene do humans inherit from their parents?

• One from the father only

• One from each parent

• One from the mother only

• Two from each parent

What compensates for the presence of a non-working gene in most individuals?

• A working copy of the gene

• A non-working gene from the other parent

• A different gene entirely

• No compensation is needed

What happens if both parents pass on a non-working gene to their child?

• The child will have an autosomal recessive disorder

• The child will have a dominant disorder

• The child will be a carrier

• The child will be unaffected

In the example of Anne and John, what is the chance of their child being affected by the disorder?

• 1 in 5

• 1 in 2

• 1 in 3

• 1 in 4

If Anne passes on a non-working gene and John passes on a working gene, what will be the child's genetic status?

• The child will be affected by the disorder

• The child will be a healthy carrier

• The child will have a dominant disorder

• The child will be unaffected and not a carrier

What is the probability of Anne and John having a healthy child with each pregnancy?

• 1 in 2

• 1 in 3

• 3 in 4

• 1 in 4

What is the risk of a child being a carrier if both parents are carriers of a recessive gene?

• 1 in 4

• 1 in 3

• 3 in 4

• 1 in 2

What is the likelihood of a child inheriting two working copies of a gene from carrier parents?

• 1 in 4

• 1 in 3

• 1 in 2

• 3 in 4

What is the term used to describe relationships where the parents are related?

• Consanguinity

• Kinship

• Affinity

• Genealogy

Why are genetic disorders more common in marriages between cousins?

• Due to shared environments

• Due to different genetic backgrounds

• Due to shared grandparents

• Due to different lifestyles