PedigreesComplex Inheritance Patterns:Autosomal v. X-Linked

Pedigree

• Family Tree• Genealogy• Inheritance Diagram

• Relates parents and offspring for numerous generations• Shows relationships between parents, children,

grandchildren…• Aunts, uncles; cousins; second-cousins; distant relatives

• Are useful in tracking complex inheritance traits, genetic disorders, and sex-linked traits

How to make a pedigree

• Female: Circle• Male: Square• Line between: Parental relationship• Line down: Parent to children• Line over and connecting: Siblings• Chronological order: Left to Right• Left (oldest) to right (youngest)

• Dashed Line: Same person• Shading: Carries/has specific trait

My Pedigree: Eye Color

Tibbot Csik(bb)

Dottie Csik(Bb)

Jerry Vessey(bg)

Diane Vessey(gg)

Cindy Csik(bb)

Phil Csik(Bb)

Terry Csik(Bb)

Paul Csik(Bb)

Steven Csik(bb)

Genell Csik(gg)

Corinne Popke(bg)

Kirstin Csik(Bg)

Nick Csik(Bg)

Phil Csik(Bb)

Let’s Practice!

• Please get out Investigation 18: Punnett Square Practice• We already did Parts A, B and C last week

• SKIP the Analysis Questions

• Do Part D now

Using PedigreesSolving problems for Sex-linked traits, genetic disorders and unknown inheritance

Sex-linked traits

• A “sex-linked” trait is carried on one of the sex chromosomes

• X-linked traits are far more common in men than women

• Tracking sex-linked traits, particularly when determining if women are carriers, requires use of Pedigrees

Autosomal v. X-Linked

• Autosomes• 22 homologous chromosome pairs• Autosomal traits occur on one or more of

your AUTOSOMES• Sex Chromosomes• Sex-linked traits occur on a X or Y• Female: XX•Male: XY

Albinoshttp://www.animaltalk.us/albino-animals/

Autosomal Inheritance: Albinism

• Albino: Latin root meaning “white”• Lack of pigment: no colors

• Autosomal, Recessive trait

AA=NormalAa=Carrieraa=Albino

X-Linked Inheritance: Ocular Albinism

• Ocular: Latin root meaning “Eye”• Lack of pigment in eyes only

• X-Linked, Recessive traitXX=NormalXx=Carrierxx=Ocular Albino

XY=NormalxY=Ocular Albino

http://www.scientificamerican.com/article.cfm?id=cosmetics-animal-testing

http://ocw.tufts.edu/Content/51/lecturenotes/551169/551383

Hemophilia

• Genetic bleeding disorder: No clotting factor• IF you have hemophilia:• No clotting proteins to work with platelets

• Recessive• Rare disease

• X-Linked• More common in males• VERY rare in females

http://www.zimbio.com/Hemophilia/articles/Tds3gpcOOph/Hemophilia+Disease

The Romanova Mystery

• We will be taking on roles today to help solve the mystery of the Russian Royal family, and the would-be heir: Alexei Romanova

• We will construct a pedigree of the Victorian-era royal family to help us investigate the mysterious deaths of royals