1. SEX-LINKED TRAITS Genes for these traits are on the X chromosome ONLY Boys receive only one X chromosome, so they are more likely to inherit the disorder because it’s passed on from their mother Examples: hemophelia, color-blindness, balding

2. REMEMBER… XX=FEMALE XY=MALE

3. We write SEX-LINKED traits using X’s with a letter added, like an exponent! X B or X b

4. Colorblindness Inability to distinguish colors Affects 1 in 10 males! X B =NORMAL X b =COLORBLIND

5. Now, cross a heterozygous female with a colorblind male! X B =NORMAL X b =COLORBLIND X B X b X X b Y

6. Y XbYXbY XBXbXBXb XbXbXbXb XBYXBY XbXb XbXb XBXB

7. ANALYZE RESULTS: X B X B = X B Y= X B X b = X b Y= XbXb=XbXb= 1 female will be a carrier 1 female will be colorblind 1 male will be normal 1 male will be colorblind

8. Color vision deficiency is usually detected using colored charts called the Ishihara Test Plates. The plates consist of gray and colored dots. The patient is asked to identify the number in the middle of the circle. After the patient has identified what they see, more testing may commence. Vision test examples. Normal people should see 74. Color deficient people may see D=21.

9. A random pattern of gray level dots is first put together. A digit pattern is then added which is defined by yellow/blue variation only. Since most people with red/green colorblindness can see yellow/blue they will be able to see the digit 5 in this test pattern. Another digit pattern which is defined by red/green variation is added. Here is the pattern composed of the random brightness pattern and the red/green pattern. Finally all three are added: People with red/green deficiency will not be able to see the red/green pattern and will see the 5. People with normal vision will see both the patterns, but since the red/green is stronger than the yellow/blue, the normal person will see the digit 6.

10. Most color-blind people see normally in all other aspects other than the color of their weakened cone. Color-blind people can usually learn by experience to associate certain colors with different sensations of brightness. Many victims of the defect are unaware that they are color-blind. Weak green cone Weak red cone

11. Pedigrees are Genetic Family Trees males females normalaffected dad mom sondaughter sondaughter first bornlast born Boys are square? Girls are round? in order of birth

12. HEMOPHELIA Affects 1 in 5,000 males INHERITANCE: SEX-LINKED RECESSIVE GENETIC DISORDER SYMPTOMS: blood fails to clot  SEVERE BLEEDING Can bleed to death from minor cuts, bumps, and bruises!

13. Show the cross outcomes for X H =NORMAL X h =HEMOPHELIA X H X h X X H Y

14. Y XhYXhY XHXHXHXH XHXhXHXh XHYXHY XhXh XHXH XHXH

15. The Gene… …That changed the world

16. Cast of Characters  England’s Queen Victoria  The Russian Royal Family: the Romanovs.  The Monk Rasputin  Lenin – Russia’s Communist leader to be

17. Queen Victoria (1819 – 1901)  …Ruled England for 64 years (1837 to 1901)  …had many children.  …was a carrier for Hemophilia, which means she was…  HETEROZYGOUS!

18. II. History Queen Victoria’s Family 1881

20. The Romanovs: Tsar Nicholas II  The last Royal leader of Russia.  He was forcibly removed from power, and…  …suffice to say that he was given a true burial only in 1999 !

21. The Romanovs: Tsarina Alexandra  She was Queen Victoria’s Granddaughter.  She was also a German Princess, back in the days when royal marriages were the basis for strategic alliances.  She inherited the allele for Hemophilia (a carrier).

22. The Romanovs: The Children  There were 5 children, but only a male could be heir.  Olga (b. 11-15 -1895)  Tatiana (b. 6 -10 – 1897)  Maria (b. 6 -26 – 1899)  Anastasia (b. 6 -10 – 1901) more on her later…  Alexis (b. 8 - 12 – 1804)  Alexis is the heir…  The Tsarevich!

23. Alexei Romanov, son of Tsar Nicolas II One of the most famous hemophiliacs was Russian Prince Tsarevitch Alexei, killed along with all his family during the Russian revolution in 1917.

24. And what of the heir?  As the only male, Alexis was “destined to rule.”  As the son of a carrier of Hemophilia (Alexandra).  He had a 50% chance of inheriting the allele for the disorder… X chromosome  On the X chromosome  He did inherit it…  He was a Hemophiliac!

25. More on Alexis…  Hemophilia could be fatal because the doctors didn't know how to treat it.  Alexis was confined to bed for long periods of time.  In 1912, he had an accident that nearly cost him his life causing him severe pain and fever.  He suffered so much that he said to his mother: "When I'm dead, it will not hurt anymore, will it, Mama?“  He did survive through the help of a man named Rasputin.

26. The “EVIL” ? Monk Rasputin  Born in 1871, far from the capital of St. Petersburg.  He was neither a monk, nor a priest, but members of the Russian Orthodox fell under his sway as he entered the imperial court.

27. Rasputin’s Healing Powers?  The Hemophilia did not kill He may have stopped the Tsarevich’s screams of pain…  …But he could not Alexis… actually cure Alexis’s Hemophilia!

28. Rasputin’s Influence…  Due to his supposed healing powers, he was given unrivaled access to the Royal family.  His corruption led to the growing distrust of the monarchy by the people.

29. The First Revolution (1905)  The first revolution by the Mensheviks (those in the minority) was a failed attempt at a democratic nation.  This led later (after Rasputin became involved) to another revolution…

30. The Setting: Russia during WW1  The suffering and unrest of the Russian people was great, especially given the economic disparity and shortages during the war.  The distrust of the Tsarina added to the unrest.

31. The Communist Revolution  The 2 nd revolution was a violent one…  Lenin and the Bolshevik’s seized power in October 1917, in the midst of the chaos of World War I.

32. Vladimir IIIyich Lenin (1870 – 1924)  The father of Communism in Russia.  He led the Bolshevik revolution which led to the Union of Soviet Socialists Republics (USSR).  He is body is displayed in Moscow’s Red Square.

33. The chain of History that Followed!  The rise of Communism.  The Fall of many eastern European countries.  The Cold War.  The Development of N.A.T.O.  The buildup of the military during times of peace, at the expense of social programs.

34. The Romanovs  They were kidnapped during the revolution.  All were assassinated on 7 – 17 – 1918!  Their body’s were not found until late in the 20 th century!

35. The myth of Anastasia  It was long assumed she survived the assassination.  A Russian woman claimed for many years to be Anastasia.  …But her body was later found with the rest of the Royal family.

37. The Conclusion?  Biology cannot be separated from our lives.  It not only affects us as individuals, but it also…  Has had a profound effect on human history!  Those interested should read up on infectious disease and history!

38. It is all about MAKING CONNECTIONS !