Human Genetic Disorders and Pedigrees

Christopherson

Human Genetics: Karyotypes

46 TOTAL

23 homologous

pairs

46 TOTAL

23 homologous

pairs

Sex Chromosomes

• 2 sex chromosomes• Typical Female = XX• Typical Male = XY

Autosomes

Autosomes: Any

chromosome that’s not a sex chromosome

•44 Autosomes•22 pairs of Autosomes

Recessive Disorder

Caused by 2 recessive alleles

Albinism

Defect of melanin production that results in little or no color in the skin, hair, and eyes

Albinism

Albinism

How does it

happen?

Affected Genotype:

aa

Cystic FibrosisDisease that causes the body to produce unusually thick, sticky mucus that:

•Clogs the lungs and leads to

lung infections • Obstructs the pancreas

• Stops natural enzymes from helping the body break down and absorb food

How does it

happen?

Affected Genotype:

cc

Sickle Cell Anemia

Caused by an abnormal hemoglobin shape which causes the red blood cells to have a crescent shape.

Red blood cells carry oxygen.

How does it

happen?

Affected Genotype:

ss

Dominant Disorder

Caused by a dominant allele

Affected individuals are homozygous dominant or

heterozygous

Huntington’s Disease

Causes the break down of brain cells, (neurons) in certain areas of the brain.

Causes uncontrolled movements, loss of intellectual faculties, and emotional disturbance.

How does it

happen?

Affected Genotype: HH or Hh

Sex-Linked Disorder

Linked to sex chromosomes

Recessive Disorders – caused by recessive alleles

Color Blindness

Inability to see colors in the normal way

How does it happen?

Affected Genotypes:

XbXb

XbY

HemophiliaInability of the blood to clot properly

How does it happen?

Affected Genotypes:

XhXh

XhY

What is a Pedigree???

Diagram showing a family tree and patterns of inheritance.

Types of Pedigrees: Recessive

Affected Genotypes: bb

Unaffected Genotypes: BB or Bb

HINT: Recessive Disorders skip generations

Is the Pedigree below showing Recessive Inheritance?

Recessive Inheritance?

Recessive Inheritance?

Types of Pedigrees: Sex-linked

Affected Genotypes: XbXb or XbY

Unaffected Genotypes: XBXB or XBXb and XBY

HINT: Mainly males are affected

Is the Pedigree below showing Sex-Linked Inheritance?

Sex-linked Inheritance?

Sex-linked Inheritance?

Types of Pedigrees: Dominant

Affected Genotypes: BB or Bb

Unaffected Genotypes: bb

Is the Pedigree below showing Dominant Inheritance?

Dominant Inheritance?

Dominant Inheritance?

How many generations?What is genotype of Individual I-1?What type of Inheritance?

How many generations?What is genotype of Individual I-1?What type of Inheritance?