PEDIGREE

Question 1

Pedigree is a

Answer 1

Pedigree is a chart that describes a family’s genetic history, and how a trait is inherited over several
generations. Pedigrees can determine if one is a carrier of a particular disease/disorders.

Question 2

if there are sick people in every generation

Answer 2

meaning a dominant disease/disorder

Question 3

if there areHealthy parents and sick child

Answer 3

meaning a recessive disease/disorder.

Question 4

if there are sickness appears in both sexes

Answer 4

usually autosomal disease.

Question 5

if there are sickness appears in one sex only

Answer 5

sex linked disease

Question 6

A dominant disease…..

Answer 6

cannot skip generations. If a person has a mutated allele, he or she will be sick.

Question 7

𝑋 linked recessive…..

Answer 7

𝑋 linked recessive is more prevalent in boys than girls. A mother that is affected by such disease,
will pass on the disease to all of her boys, while a father that is affected will never pass them to his
boys.

Question 8

𝑋 linked dominant in a sick father ….

Answer 8

𝑋 linked dominant in a sick father will always pass on to his girls the mutated allele and making
them sick, but never to his boys. A heterozygote mother will a 50% change to have a sick child
regardless its gender, while a homozygote will have all of her children sick.

Question 9

Dominant Autosomal

Answer 9

An offspring that inherits the mutated gene will be affected, no matter if they are homozygote or

heterozygote.
* Abnormal genes found on autosomes.
* Both males and females are equally effected.
* Usually appears in every generation.

Question 10

Autosomal Recessive

Answer 10

An offspring that is heterozygote (carrier) will not be affected by the disease, but a homozygote one will
be affected by it.
* Abnormal genes found in autosomes.
* Both males and females are equally affected.
* Can skip generations. Non affected carrier parent can produce sick offspring

Question 11

X-Linked Disorders

Answer 11

Diseases caused by abnormal genes on sex chromosomes. Most common are 𝑋-liked abnormal gene of the X chromosome.

• Absence of father-son transmission.
• Affected father will result is all daughters either sick or carriers, depends on whether the trait is 𝑋-liked dominant or 𝑋-liked recessive.
• Males will always be sick, regardless the characteristics of the 𝑋-liked disease. Whether its recessive or dominant, males have only one 𝑋 chromosome. Thus, they will always be sick.
• Nearly all 𝑋-liked disorders are recessive.

Question 12

𝑋-Liked Dominant

Answer 12

Very rare mode of transmission where the abnormal gene on the 𝑋-chromosome is always expressed.

• Females are usually more affected by 𝑋-liked dominant disease.
• Affected father will have 100% sick daughter and 100% healthy boys.
• Affected mother will have 100% affected offspring regardless its gender.

Question 13

𝑋-Liked Recessive

Answer 13

Transmission where the abnormal gene on the 𝑋-chromosome is not always expressed.
* Males are more affected by 𝑋-liked recessive diseases then females.
* Females have ability to be carriers if the abnormal gene is located on only one of their 𝑋chromosome (heterozygote). It can be inactivate and be compensated by the other 𝑋 chromosome.
* Affected father will have 100% carrier daughters and 100% healthy boys.
* Affected mother will have 50% carrier daughters and 50% sick boys. For a daughter to be sick she
need to have a carrier mother and a sick father.

Question 14

𝒀-Linked Disorders

Answer 14

Transmission where the abnormal gene is on the 𝑌-chromosome.

• There aren’t many 𝑌-linked disorders.
• Always affect males.
• Inherited from affected father to his sons.