1 / 22

Notes: Pedigrees

Explore the orderly diagram of a family's genetic traits through pedigrees. Learn about relationships, genotypes, phenotypes, and allele dominance in both autosomal and sex-linked traits. Symbols and patterns explained with examples like Huntington's disease and Cystic Fibrosis.

rayrichardson
Download Presentation

Notes: Pedigrees

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. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Notes: Pedigrees Orderly diagram of a family’s genetic traits

  2. A pedigree shows… • relationships, sex, genotype & phenotype of each member • if an allele is dominant or recessive • if an allele is autosomal or sex-linked

  3. Symbols • Circle = female • Square = male • Horizontal line = parents • Vertical line = children • Symbol w/line through it = dead

  4. More symbols • Half-Shaded = heterozygous not affected (recessive disorder) • Completely darkened = homozygous affected • Half-Darkened = heterozygous affected (dominant disorder)

  5. Pattern #1- Autosomal Dominant • In general, males & females equally affected • NO skipping generations • Trait is expressed if allele is present

  6. AD EX: Huntington’s disease • Build up of protein causes damage to nerve cells in brain • Most people develop symptoms in 40s-50s • Symptoms start w/movement problems, slurred speech, balance problems, swallowing difficulties Huntington disease (right) showing a larger cavity where brain cells have died, compared with a normal brain (left).

  7. Pattern #2 – Autosomal Recessive • In general, males & females equally affected • Can skip generations • Both parents are carriers • Trait is expressed only if homozygous

  8. AR EX: Cystic Fibrosis • Defective chloride-ion transport protein in cell membranes • Symptoms – thick, heavy mucus clogs lungs, liver, pancreas • Most people do not survive past late 30s • Many treatments for symptoms, but NO cure

  9. Pattern #3 - Autosomal • In general, males & females equally affected • Father-child transmission of trait

  10. Pattern #4 – Sex-linked recessive • In general, more males are affected than females • If mom is carrier  sons are affected, not daughters • If dad is affected  daughters are carriers • NO dad-son transmission • NO male carriers

  11. EX: Red-Green Color Blindness • Affects males more than females • 3 types of cone cells working together give you color vision (red, blue, green)

  12. EX: Hemophilia • Affects males more than females • Missing blood clotting proteins • Lots of bleeding from minor cuts • Can suffer internal bleeding from bumps/bruises • Can be treated w/injections of clotting proteins

  13. Try this one • Autosomal dominant

  14. Autosomal recessive

  15. Dominant - Autosomal

  16. Recessive - Autosomal

  17. Recessive, X-linked

  18. Recessive - Autosomal

  19. Dominant - Autosomal

  20. Recessive, X-linked

  21. Autosomal recessive

  22. X-linked recessive

More Related