Patterns of Inheritance

Pedigree

a genetic family tree that shows how prevalent a trait is in a family unit from generation to generation.

Pedigree

often used to track the expression of genetic conditions and disorders

• Males

• Females

• Squares represent?

• Circles represent?

colored

A ______ in shape means that person has the trait in question

half colored

means that they are carrying an allele for a recessive trait

Autosomal

_______ means not on the sex chromosomes

Autosomal Dominant Inheritance

refers to those situations in which a single copy of an allele is sufficient to cause expression of a trait

• one affected parent

• equally

• 50%

Autosomal Dominant Inheritance:

• Every affected person should have at least ____ ________ ______

• Males and Females should be ____ often affected

• An affected person has at least ___ chance of transmitting the dominant allele to each offspring

• Progeria

• Huntington's Disease

Autosomal Dominant Inheritance Examples:

Progeria

(caused by a mutation) which the person ages very rapidly.

• They die before they can reproduce

huntington’s Disease

in which the central nervous system starts to break down around the age of 30

Hutchinson-Gilford syndrome

• Moodiness

• Fidgeting

• Cognitive Issues

• Personality shifts

• Depression

• Trouble focusing

• Muscle twitching

Huntington's early symptoms:

Autosomal Recessive Inheritance

refers to those situations where two recessive alleles result in a trait being expressed

• carriers

• equally

• 2 affected parents, 100%

Autosomal Recessive Inheritance:

• An affected person may not have affected parents. Parents would be _____

• Affects both sexes _____. Can appear to skip generations

• ___ ________ ____ will have affected children ____ of the time.

• Albinism

• Tay Sachs

Autosomal Recessive Inheritance Examples:

Albinism

genetic condition which is the loss of pgiment of hair, skin, eyes

Tay Sachs

a genetic disorder whoch is a build up of fatty deposits in the brain, eventually to be fatal

X - Linked Recessive Inheritance

refers to those situations where a recessive allele on the X chromosome can lead to a trait/condition or disorder

• Males, 8:1

• daughters, sons

• Homozygous recessive females

X linked Recessive Inheritance:

• ____ are affected more. Ratio of ___.

• Affected males will transmit the allele to all _____, but not to _____

• _________ _________ ______ can arise only from matings in which the father is affected and the mother is affected or a carrier.

• Hemophilia

• Duchenne Muscular Dystrophy

X Linked Recessive Disorders:

Hemophilia

inability of the blood to clot properly

Duchenne Msucular Dystrophy

which causes progressive and degenerative muscle weakness

X - Linked Dominant Inheritance

Refers to situations where a single dominant allell on X chromosome can lead to trait/condition

• females

• half the children

• daughters

X Linked Dominant Inheritance:

• Twice as many ____ are affected

• Usually_________ of an affected female will be affected, regardless of sex

• All the ______ of an affected male will be affected but none of the sons

Vitamin D resistant rickets

X Linked Dominant Example:

Vitamin D resistant rickets

can lead to bone deformities, particularly in the lower limbs (bowed legs)

Y - Linked Inheritance

inheritance of genes on the Y chromosome.

father to son

Since only males normally have a Y chromosome, Y linked genes can only be transmitted from ____ to ____

• Hypertrichosis of the ears

• Webbed toes

Y linked inheritance Examples: