Unit 4 Human Genetics Pedigree

Basic Pedigree symbol

Hemophilia B

______ _ is due to mutation in the FIX gene that I activates blood clotting factor IX

Autosomal

_______ recessive medical traits are due to mutations in genes on the autosomes (1-22)

Pedigree analysis for autosomal traits

• No Affected Individuals In Some Generations

• Affected Children Have Unaffected (Wild-Type) Parents

• Female & Male Children Equally Affected

Autosomal recessive traits

• Albanian

• Beta-thalassemia

• Cystic fibrosis

• PKU

• Sickle cell disease

• Tay-sachs disease

Inbreeding

Autosomal recessive traits relate to _____

• The Parents Of The Affected Child Share A Common Ancestor

• The Common Ancestor Is The Source Of The Mutated Allele

• Most Medically Relevant Recessive Alleles Are Rare In The Human Population

Autosomal Dominant

______ ______ medical traits are due to mutations in genes on the autosomes (1-22)

One Or Two Copies Of The Mutated Allele Cause Trait Expression

• Haplo-Insufficiency Hypothesis

• Low Protein Concentration Prevents Its Cellular Function

• Rogue Protein Hypothesis

• Abnormal Protein Disrupts Cellular Processes

Haploinsufficency

When one copy of an allele is not enough

Pedigree analysis for autosomal dominant traits

1) Affected Individual(s) In Every Generation

2) Affected Children Have An Affected Parent

3) Affected Parents Transmit The Trait Equally To Female & Male Children

Autosomal dominant traits

• Achondroplasia

• Familial Hypercholesterolemia

• Huntington’s disease

• Marfan syndrome

• Polycystic Kidney Disease

X-linked

______ recessive medical traits are due to mutations in genes on the X chromosome

______ recessive traits are expressed in:

• females with 2 copies of the recessive allele

• Males with one copy if the recessive allele

Pedigree analysis for X-linked recessive traits

1) Some Generations Are Unaffected

2) All Affected Individuals Are Male

3) Affected Males Have Carrier Daughters

X-linked recessive traits

• Hemophilia A & B

• Duchenne Muscular Dystrophy

• Red-Green Colorblindness

• X-Linked Agammaglobulinemia (XLA)

X-linked dominant

_____ ______ medical traits are due to mutations in genes on the X chromosome

Pedigree analysis for X-linked dominant traits

1) Affected Individuals In Every Generation

2) Affected Children Have An Affected Parent

3) Affected Males Have All Affected Daughters & No Affected Sons

Cytoplasmic inheritance of traits

Genes In The Mitochondrial Genome Control Some Traits

 Transmission Is -

• Always From The Mother

• Never From The Father

 We Inherit Our Mitochondria From Mother’s Egg