Genetics Case Study: The Royal Family

The Romanov Family Romanov Empire included one-sixth of the globe. Nicholas II became Czar of Russia in 1896 Resentment against the Czar and wealthy class begins at end of 19th century.

Alexei Born in 1904, Nicholas’s only son. Had hemophilia, a bleeding disorder. Had body guard with him at all times to prevent accidents. Alexei had several internal bleeding instances. These bleedings were stopped after the prayers of the healer Rasputin.

Rasputin Healer or Scoundrel???? Alexandra (Alexei’s mom) called Rasputin in to stop Alexei’s bleeding. Alexandra took Rasputin in as a relative (which lowered public faith of the Romanov family). His influence on the Czar is arguable by historians. Assassinated by Russian aristocrats.

Rasputin Rasputin was drugged, poisoned, and shot before he died of drowning in the Neva river

End of the Empire July, 1918: Russian Revolution (Romanov’s assassinated) Alexei’s body missing from mass grave found in 1990’s.

So what does this have to do with Genetics? Learn how to read a PEDIGREE. Learn the inheritance pattern of HEMOPHILIA.

Sex-Linkage Traits controlled by genes located on the sex chromosomes are called sex-linked traits. The gene for a protein that helps blood clot is on the X chromosome. If this gene is mutated (deletion, point mutation, etc), it may cause HEMOPHILIA. Heterozygotes are carriers & may pass trait on to children, but themselves appear normal. Other sex-linked traits are red-green colorblindness, Duchenne muscular dystrophy, and Fragile X syndrome.

Royal Family Pedigree

Pedigrees Each row represents a generation Genders represented by different shapes Affected individuals indicated by shading Carriers indicated by half shading

Reading a Pedigree Sometimes, carriers are indicated this way.

Pedigree Problems: Tips Recessive: trait usually skips a generation Dominant: trait shows up often Autosomal: trait seen in both genders Sex-linked: trait seen usually in 1 gender

Sample Pedigrees

Dominant or recessive trait? Autosomal or sex-linked? Pedigree Practice Dominant or recessive trait? Autosomal or sex-linked?

Dominant or recessive trait? Autosomal or sex-linked? Pedigree Practice Dominant or recessive trait? Autosomal or sex-linked?

Dominant or recessive? Autosomal or Sex-linked? Pedigree Practice Dominant or recessive? Autosomal or Sex-linked?

Practice Problems http://www.yhc.edu/external/jasonb/previous_semesters/Bio103_Su2004/Links_of_Interest/links_to_practice_pedigree_probs.htm

Create your own pedigree! Draw your family tree like the pedigrees we’ve seen. Decide on a trait, and shade the affected individuals. (see list of traits on next slide) Show the trait through 3 generations in your family (grandparents, parents, and you and your siblings).

Dominant Recessive Widow’s peak hairline Straight hairline Tongue-rolling Can’t roll tongue Free earlobes Attached earlobes Can’t bend back 45° Hitchhiker’s thumb Freckles No freckles No chin cleft Chin cleft Bent little finger Not bent Oval face Square face Morton’s Toe(2nd toe) Big Toe is tallest Dark hair (brown/black) Blonde Hair Not red hair Red Hair