Today is Wednesday, December 18 th , 2013

1. In This Lesson: Pedigrees, Linked Genes, and the Human Genome Project (Lesson 6 of 6) Today is Wednesday,December 18th, 2013 Pre-Class: What runs in your family? Please turn in your Donor Match Blood Type Game worksheets.

2. Today’s Agenda • Finish Who Gets the Money! • Pedigrees! • Linked genes! • Exclamation points! • Where is this in my book! • P. 279 and following…!

3. Linked Genes • Genetics is further complicated by the fact that some traits are linked. • This means that some genes are carried on the same chromosome. • Why is that important? • This means that they will be inherited together. • “Huh?” said the class.

4. Linked Genes • Think of people that have blonde hair and blue eyes. As it turns out, eye and hair color are near one another on the chromosome, meaning that often times people of a certain hair color also have a certain eye color. • But why? • First, let’s look at a diagram.

5. Linked Genes • Linked genes are often kept together despite the process of crossing over in meiosis (remember that?). • When two genes are linked (inherited together), typically there are fewer possibilities for gametes.

6. Pedigrees • You’ve probably heard the term before for dogs. Here’s the biology definition… • “A pedigree is a diagram of family relationships that uses symbols to represent people and lines to represent genetic relationships.” • Makes it easy to look at the way genes are passed through large families. • Vertical lines represent offspring and new generations. • Horizontal lines show marriage/crosses and related siblings. http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/Bio%20101/Bio%20101%20Laboratory/Pedigree%20Analysis/PEDIGREE.HTM - AND ALL FOLLOWING

7. Sample Pedigree • In this, and most examples, males are squares and females are circles. • Probably easy to remember. • First generation at the top, newer below.

8. Sample Pedigree • “Affected” individuals have filled-in shapes. • In other words, pedigrees only look at one particular phenotype, not multiple traits or genotypes. • Carriers tend to be half-shaded (but not always).

9. Pedigree Practice Problems Aa aa 1 2 In this pedigree, sickle cell anemia (a) is recessive to wild type blood (A). Give the genotypes for each of the individuals shown. (Blue is “affected”) aa Aa 3 4

10. Pedigree Practice Problems 2 1 Does this pedigree illustrate a dominant or recessive trait? (blue is shaded) Think carefully! Use Punnett Squares! Italics! 3 4 5

11. Pedigree Practice Problems • This trait could be dominant or recessive. Recessive Dominant rr Rr Rr rr Rr rr Rr rr Rr rr

12. Using a Pedigree • Look at this portion of a full pedigree: • Could this pedigree possiblyillustrate a dominant trait? • Why or why not? This pedigree could not illustrate a dominant trait because neither parent has a dominant allele. 1 bb 2 bb 3 B? 4 bb

13. Using a Pedigree • Look at this portion of a full pedigree: • Could this pedigree possiblyillustrate a dominant or recessive trait? • Why or why not? This pedigree could illustrate a dominant or recessive trait because one of the parents and offspring express the trait. 1 bb Bb bb 2 Bb Recessive Dominant Bb bb 3 4 Bb bb

14. Other Pedigree Examples http://biology.clc.uc.edu/Courses/bio105/sex-link.htm

15. Sex-Linked Traits and Pedigrees • Don’t lose your royal family pedigree. It is going to be our guide to both pedigrees and more sex-linked traits. • Not to be confused with linked traits. • This is a big pedigree. Where do we start? • First, some highlights: • See “JC” over on the right side? That’s the current king of Spain, Juan Carlos. • Locate Olga, Tatiana, Marie, Anastasia, and Alexei near the middle of the pedigree. Then look at their parents. Recognize them? • P.S. The whole family was executed – the kids were between 13 and 22 years of age at the time. • Find Prince Charles in the lower left. His wife was Princess Diana. Their son is Prince William (of Royal Wedding fame).

16. But then there’s Queen Victoria • She’s the second “Victoria” from the top. • Reigned from 1837 to 1901. • That’s 63 years! • 9 children, 42 grandchildren. • Carrier of hemophilia. http://en.wikipedia.org/wiki/Victoria_of_the_United_Kingdom

17. Hemophilia • Queen Victoria was a carrier (through mutation) of the gene for hemophilia. • Hemophilia is a blood disorder in which clotting is slow to occur and “bleeding out” is likely. Larger wounds can be fatal. • The gene is recessive, andis on the X-chromosome. • Thus, sex-linked (or X-linked).

18. How This Works • Let’s cross a normal male with a female that carries colorblindness (but does not express it): • What are the chances of a colorblind child? • What are the chances of a colorblind girl?

19. Generally speaking… • Males are more susceptible to X-linked recessive traits than females. • A male only has one X-chromosome, so even a recessive allele will give him the trait. • How would it be possible to have a colorblind female child without a colorblind mother? • Take five minutes, talk to your neighbor, and write down an answer in your notebooks. Punnett Squares help.

20. Colorblindness in Females • Mom is not colorblind (but is a carrier). • Dad is colorblind.

21. Another example… • Let’s start at Victoria(the first one). • Yes, you should take notes on what I’m about to say… Pedigrees from http://www.sciencecases.org/hemo/hemo.asp and http://biology.clc.uc.edu/Courses/bio105/sex-link.htm

22. Generations • P Generation = 1st Generation • P stands for Parental • Edward and Victoria on this pedigree. • F1 Generation = 2nd Generation • P Generation’s offspring. • Albert and Victoria on this pedigree. • F stands for Filial (as in “first filial generation”) • F2 Generation = 3rd Generation • F1 Generation’s offspring. • Victoria’s nine children on this pedigree.

23. Generations • Important note: • If I decide I don’t want to start by looking at Victoria and Edward but instead start analyzing gene flow in just the Russian Royal Family (with Czar Nikolas and Alix), they become the P generation. • The F1 Generation is now Olga, Tatiana, Marie, Anastasia, and Alexis.

24. Royal Family Pedigree • Victoria’s F1 generation: • There is a gentleman named Leopold. What is his genotype? • X’Y (he’s hemophilic) • There is also Alice. What’s her genotype? • XX’ • Who gave her the X’ allele? Mom or Dad? • Mom did. Albert (Dad) doesn’t have that allele or his genotype would be X’Y, making him hemophilic.

25. Pedigree Activity • Purpose: To get to know pedigrees just a little better. • What you’ll be doing: Working with your partner to create two pedigrees - one illustrating a dominant trait, the other, a recessive trait. • And then: You’ll exchange these pedigrees with another team, who will “evaluate” them and try to see if they can guess which is recessive and which is dominant.

26. The Human Genome Project • So what’s a genome? • A genome is all the DNA in an organism. • Example: The human genome, the fruit fly genome, the corn genome… • Video

27. The Human Genome Project • Started 1990, completed in 2003. • Accomplishments: • Identified nearly all 20,000 – 25,000 genes in humans. • Determine nearly all of the base pair sequences in humans (approximately 3 billion of them). • Sequenced genes of fruit flies, brewer’s yeast, roundworms. • Spun-off a large bioethics program.

28. Closure • Time for a WhipAround!