1 / 8

Pedigrees

Pedigrees. Pedigree charts show a record of the family of an individual. It can be used to study the transmission of a hereditary condition (genetic disease). It is particularly useful when there are large families and a good family record over several generations. Used in humans & animals.

cdonnell
Download Presentation

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. Pedigrees • Pedigree charts show a record of the family of an individual. • It can be used to study the transmission of a hereditary condition (genetic disease). • It is particularly useful when there are large families and a good family record over several generations. • Used in humans & animals.

  2. I, II, III 1, 2, 3 Children (in birth order) Non-identical twins Carrier (heterozygote) Died in infancy Generations Affected male Identical twins Normal male Affected female Normal female Sex unknown Pedigree Analysis Symbols are used to represent males, females etc. For traits of interest, symbols can be shaded to indicate individuals carrying the trait. Individuals are designated by their generation number and then their order number in that generation.

  3. Pedigree Charts:

  4. Pedigree Chart Symbols Males, Females, married, children, siblings, affected, normal Carrier (heterozygote)

  5. Inheritance of Dominant Traits • In the inheritance of autosomal dominant traits, each affected individual will have at least one parent who is also affected. • If large number sof families are examined equal numbers of males and females are affected. • Inheritance of the rare trait woollyhair in humans follows this pattern. • In the 1st generation, female I-2is heterozygous for a woolly hairallele. • Half of her offspring are alsoheterozygous for the woolly hairallele, where t is expressed. The the rest (II-5, II-6, II-7) arehomozygous recessive andhave normal hair.

  6. Inheritance of Recessive Traits • The pedigree for albinism (lack of pigment in the hair, skin and eyes) is inherited as an autosomal recessive trait. • The trait is not sex linked and is shown by both males and females. The affected female in the third generation has phenotypically normal parents. • All generation II offspringare carriers for the albinoallele. • III-2 is an albino girl whosepaternal grandmother andmaternal grandfather arealso albinos. • All her other relatives are phenotypically normal.

  7. Is this a recessive or dominant disease?

  8. Sex Linked Hemophilia In the Royal Family

More Related