Pedigrees and Karyotypes

Pedigrees and Karyotypes

A chart that shows the presence or absence of a trait according to the relationships within a family across generations

Pedigree

A circle represents a female.

A square represents a male.

A horizontal line connecting a male and female represents a marriage.

A vertical line and a bracket connect the parents to their children.

A half-shaded circle or square indicates that a person is a carrier of the trait.A completely

shaded circle or square indicates that a person expresses the trait.

A circle or square that is not shaded indicates that a person neither expresses the trait nor is a carrier of the trait.

Autosomal DominantEx Achondroplasia Dwarfism, Huntington’s

Disease, Inherited colon & breast cancer, hypercholesterolemia

Autosomal RecessiveEx Sickle Cell Disease, Cysic Fibrosis,

Phenylketonuria (PKU), Recessive blindness, Tay Sachs

Modes of Inheritance

X-linked DominantEx Hypophosphatemic rickets, Rett Syndrome,

Incontinentia pigmenti (lethal in males), congenital generalized hypertrichosis (wolf man syndrome)

X-linked RecessiveEx Dushene Muscular Dystrophy, hemophilia,

color blindness

Modes of Inheritance

Autosomal DominantTransmitted directly

from one generation to the next.

Males and Females affected equally

NEVER SKIPS A GENERATION

Never any carriers

Autosomal RecessiveOnly expressed when in

homozygous form

Males and females affected equally

May skip many generations before showing up

¼ chance being affected when carriers mate

X-linked DominantFemales affected

more frequently

Daughters of affected males : 100% chance & sons: unaffected

Offspring of affected females : 50% chance

X-linked RecessiveMales affected more

frequently because they only have one X chromosome

Typical transmission from carrier female

X-linked Recessive ContinuedSometimes carriers

are not depicted on the pedigree

What mode of Inheritance?

What Mode of Inheritance?

Cystic Fibrosis

What Mode of Inheritance

Huntington’s Disease

What Mode of Inheritance?

Hypertrichosis

What Mode of Inheritance?

Sickle Cell Anemia

What Mode of Inheritance?

Duchenne Muscular Dystrophy

What Mode of Inheritance?

Tay-Sachs

Karyotypes

Definition

A karyotype is the characteristic

chromosome match (or complement) of a eukaryote species

Human Male

Human Female

Human Gametes

Down Syndrome

Klinefelter Syndrome

Turner Syndrome

What is Wrong Here?

Dog Karyotype

Mouse Karyotype

Chromosome Number By Species

Common Name Genus and Species Diploid Chromosome

Number

Buffalo Bison bison 60

Cat Felis catus 38

Cattle Bos taurus 60

Dog Canis familiaris 78

Donkey E. asinus 62

Goat Capra hircus 60

Horse Equus caballus 64

Human Homo sapiens 46

Pig Sus scrofa 38

Sheep Ovis aries 54