1 / 11

Pedigree Analysis

Pedigree of Queen Victoria. Pedigree Analysis. Have you ever seen a family tree… do you have one?? Graphic representation of family inheritance. What is a pedigree? . A chart that shows a pattern of inheritance in a family for a specific trait (phenotype)

cardea
Download Presentation

Pedigree Analysis

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. Pedigree of Queen Victoria Pedigree Analysis Have you ever seen a family tree… do you have one?? Graphic representation of family inheritance.

  2. What is a pedigree? • A chart that shows a pattern of inheritance in a family for a specific trait (phenotype) • Why would we want to use a pedigree in genetics? • Track the occurrence of diseases such as: • Huntington’s – simple dominant – lethal allele – causes breakdown of the brain • Cystic fibrosis – 1/2500 – mucus accumulates (white North Amer.) • Tay-Sachs disease – lipids accumulate in CNS (Jewish) • Phenylketonuria – missing enzyme causes problems in CNS (Nordic/Swedish)

  3. The Symbols used:

  4. Sample pedigree: • generations are numbered with Roman Numerals • oldest offspring are on the left How many males are present? How many females? How many females show the trait being studied? What is the sex of offspring III-9? How many offspring did the generation I parents have? What is the difference between the II-3 & 4 and IV-2 & 3?

  5. Inheritance patterns: • Autosomal dominant: • The disease occurs in consecutive generations(does not skip a generation) • Males and females are affected, with the same probability. • Ex.: Polydactyly • Huntington’s disease

  6. Fig. 14-17 Parents Dwarf Normal Dd dd  Sperm D d Eggs dd Dd d Dwarf Normal Dd dd d Normal Dwarf

  7. Inheritance patterns: • Autosomal recessive • Males and females are equally likely to be affected. • The trait is characteristically found in siblings, not parents of affected • It generally skips a generation Parents of affected children may be related. • Ex. : Cystic fibrosis • Tay-Sach’s disease

  8. Fig. 14-16 Parents Normal Normal Aa Aa  Sperm a A Eggs Aa AA Normal (carrier) A Normal Aa aa Normal (carrier) a Albino

  9. Inheritance patterns: • Sex-linked recessive conditions • The disease is never passed from father to son.Males are much more likely to be affected than females. • All affected males in a family are related through their mothers.It generally skips a generation • Ex.: - Colour-blindness • Hemophilia

  10. Human disorders • Testing: •amniocentesis •chorionic villus sampling (CVS) • Examination of the fetus with ultrasound is another helpful technique

More Related