BIO 260 Pedigrees
1. Pedigree: pictorial representation of a family history; a family tree that outlines the inherita nce of one or more
characters
2. Proband: The person from whom the pedigree is initiated
-Usually designated by an arrow
it. (affected by
3. Penetrance: proportion of individuals carrying a specific dominant allele, and also show the tra
env. and genetic background)
=Ex. BRCA1 gene allele shows 80% penetrance; the lifetime
chance of getting breast cancer is 80%
4. • Autosomal recessive traits
• Autosomal dominant traits
• X-linked recessive traits
• X-linked dominant traits
• Y-linked traits: Types/Modes of Inheritance patterns observed w/ pedigrees
5. Autosomal Recessive Traits: -equal appearance of trait in B
s and @
s
1/3
, -skips generations
llele.
-can result from consanguine mating (inbreeding); both parents are likely to carry a recessive a
-ex. CF; Sickle Cell
6. Autosomal Dominant Traits: -equal appearance of trait in B
s&@
s
-present in all generations
-if not present, due to mutation of the allele or incomplete penetrance
-ex. GSS on chr20
-ex. BRCA1 on chr17
7. X-linked recessive traits: -appear more often in males than in females
-is not passed from father to son.
- ex. Hemophilia; colorblindness
8. Hemophilia: An X-linked recessive disorder in which blood fails to clot properly, leading to excessive bleeding
if injured.
9. X-linked dominant traits: • affects both B
s&@
s
• present in all generations
2/3
1. Pedigree: pictorial representation of a family history; a family tree that outlines the inherita nce of one or more
characters
2. Proband: The person from whom the pedigree is initiated
-Usually designated by an arrow
it. (affected by
3. Penetrance: proportion of individuals carrying a specific dominant allele, and also show the tra
env. and genetic background)
=Ex. BRCA1 gene allele shows 80% penetrance; the lifetime
chance of getting breast cancer is 80%
4. • Autosomal recessive traits
• Autosomal dominant traits
• X-linked recessive traits
• X-linked dominant traits
• Y-linked traits: Types/Modes of Inheritance patterns observed w/ pedigrees
5. Autosomal Recessive Traits: -equal appearance of trait in B
s and @
s
1/3
, -skips generations
llele.
-can result from consanguine mating (inbreeding); both parents are likely to carry a recessive a
-ex. CF; Sickle Cell
6. Autosomal Dominant Traits: -equal appearance of trait in B
s&@
s
-present in all generations
-if not present, due to mutation of the allele or incomplete penetrance
-ex. GSS on chr20
-ex. BRCA1 on chr17
7. X-linked recessive traits: -appear more often in males than in females
-is not passed from father to son.
- ex. Hemophilia; colorblindness
8. Hemophilia: An X-linked recessive disorder in which blood fails to clot properly, leading to excessive bleeding
if injured.
9. X-linked dominant traits: • affects both B
s&@
s
• present in all generations
2/3
