Module 4 Flashcards
Rules that explain the common patterns of single-gene transmission
Modes of inheritance
Passing of a trait depends on whether:
- Determining gene is on an autosome or on a sex chromosome
- Allele is recessive or dominant
*Affects both sexes and appears every generation
Autosomal Dominant Inheritance
What disease is an example of Autosomal Dominant Inheritance
Huntington’s disease
*Males and females can be affected.
*Affected males and females can transmit the gene, unless it causes death before reproductive age.
*Trait can skip generations.
*Parents of an affected individual are heterozygous or have the trait.
Autosomal Recessive Inheritance
what disease is an example of Autosomal Recessive Inheritance
Cystic fibrosis
which mode of inheritance is the following Punnett square?
Hh = affected
hh = normal
Autosomal Dominant Inheritance
which mode of inheritance is the following Punnett square?
Hh = carrier
hh = affected
Autosomal Recessive Inheritance
Affected individual has an affected
parent, unless he or she has a de
novo mutation
Autosomal Dominant
Affected individual has parents who
are affected or are carriers
(heterozygotes)
Autosomal Recessive
X-linked traits are passed like
autosomal traits
Females
A single copy of an X-linked allele causes expression of the trait or illness
Males
Human male is considered _________ for X-linked traits
hemizygous
-Always expressed in the male
-Expressed in a female homozygote and very rarely in a female heterozygote
-Affected male inherits trait from heterozygote or homozygote mother
-Affected female inherits trait from
affected father and affected or
heterozygote mother
X-Linked Recessive Trait
-Expressed in females in one copy
-Much more severe effects in males
-High rates of miscarriage due to
early lethality in males
-Passed from male to all daughters
but to no sons
X-Linked Dominant Trait
What X-Linked Trait is the following?
XRXr = Affected Female
XRY = Affected male
XrXr = Normal female
XrY = Normal Male
X-Linked Dominant
What X-Linked Trait is the following?
XRXC = Normal Female
XCY = Normal Male
XCxc = Carrier Female
XcY = Affected Male
X-Linked Recessive
Genes on the Y chromosome are said to be ________
Y-linked
symbolic representations of
family relationships and the transmission of inherited traits
Pedigrees
A diagram that shows the occurrence and appearance or phenotypes of a particular gene or organism and its
ancestors from one generation to next
Pedigree Chart
- Describes the process of interpretation of information displayed as a family tree or chart
- Used to work out the probability that someone in a family will inherit a condition
Pedigrees
True or False
A father transmits his allele of X-linked genes to his daughters, but not his sons
True
True or False
A mother transmits an allele of X-linked genes to both her daughters and her sons
True
Does not skip generations, can affect both sexes
Autosomal Dominant Trait
- Trait is rare in pedigree
- Trait often skips generations (hidden in heterozygous carriers)
- Males and females equally likely to be affected
Autosomal Recessive Trait
