Chapter 12 3
1 / 8

Chapter 12.3 - PowerPoint PPT Presentation

  • Uploaded on

Chapter 12.3. Examples of Autosomal Inheritance Patterns. AP Biology Fall 2010. Autosomal Dominant Inheritance. The dominant allele is nearly always expressed, even in heterozygotes

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Chapter 12.3' - sophie

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Chapter 12 3 l.jpg

Chapter 12.3

Examples of Autosomal Inheritance Patterns

AP Biology

Fall 2010

Autosomal dominant inheritance l.jpg
Autosomal Dominant Inheritance

  • The dominant allele is nearly always expressed, even in heterozygotes

  • If one parent is heterozygous and the other homozygous recessive, there is a 50 percent chance that any child will be heterozygous

    • Draw a punnette square to illustrate this

    • Cross a normal mother with an affected father

      • aa x Aa

      • aa = normal

      • Aa = affected

Autosomal dominant inheritance3 l.jpg
Autosomal Dominant Inheritance

  • If the gene (and its resulting disorder) reduces the chance of surviving or reproducing, its frequency should decrease

    • May not due to mutations, nonreproductive effects, and post reproduction onset

Autosomal dominant inheritance4 l.jpg
Autosomal Dominant Inheritance

  • Achondroplasia (dwarfism): is a benign abnormality that does not affect persons to the point that reproduction is impossible

    • The gene is passed on in heterozygotes

Autosomal dominant inheritance5 l.jpg
Autosomal Dominant Inheritance

  • Huntington disease is a series degeneration of the nervous system with an onset past the mid-thirties

    • By which time the gene has (usually) been passed from parent to offspring unknowingly

Autosomal recessive inheritance l.jpg
Autosomal Recessive Inheritance

  • Characteristics of this condition:

    • Either parent can carry the recessive allele on an autosome

    • Heterozygotes are symptom-free carriers

    • Homozygotes are affected

    • Two heterozygous parents have a 50 percent chance of producing heterozygous children and a 25 percent chance of producing a homozygous recessive child

    • When both parents are homozygous, all children will be affected

  • Try crossing a carrier mother (Aa) with a carrier father (Aa)

Autosomal dominant inheritance7 l.jpg
Autosomal Dominant Inheritance

  • Galactosemia: the inability to metabolize lactose

    • Is an example of autosomal recessive inheritance in which a single gene mutation prevents manufacture of an enzyme needed in the conversion pathway

What about neurobiological disorders l.jpg
What About Neurobiological Disorders?

  • Patterns of Mendelian genetics are not followed by human neurobiological disorders

  • In most cases a lone gene does not give rise to disorders such as: depression, schizophrenia, or bipolar

  • Researches predict that having certain mutant autosomal alleles increases the chance of developing schizophrenia

    • Mutant alleles are also linked to bipolar disorder and depression