Genetics

1. Genetics History Patterns of Inheritance Applied Genetics

2. Case Study: In 1917 the average farmer wanted cows that would produce both milk and beef. Short horn (Durham) cows were popular with the farmers because they had large calves to sell for beef and gave a reasonable amount of milk. The condensed milk factories that bought the farmers’ milk wanted the farmers to keep Holsteins because they produced large quantities of milk. When the milk factories demanded Holstein cows, rather than buy a whole new herd, many farmers got together and purchased a Holstein bull and introduced the breed into their herds. The result was a cow that gave more milk, but still had a large, if not quite so beefy, calf. History • For thousands of years farmers have selectively bred animals to get the traits they want. • Farmers mate one animal with qualities they want with another with qualities they want hoping to get animals with both qualities.

3. Father of Genetics…. • Gregor Mendel – 1822 • Mendel was an Austrian (not Australian) monk. • He notice 2 black horses that had a tan foal and wondered how that could happen? (no she wasn’t cheating ) • At the monastery he worked in the garden. • It was here that he noticed pea plants had 6 different characteristics (traits).*see next slide • He observed some traits disappeared and then reappeared in later generations. • Baby step through punnet squares • http://users.adelphia.net/~lubehawk/BioHELP!/psquare.htm

4. Mendel contd… • Why peas? • Grow Quickly • Many different varieties. • Self-pollinating

5. Mendel contd… • Studying on trait at time. Mendel used only purebreds for each trait. (TT, tt) • Mendel’s 1st experiment: • Round vs Wrinkled • He mated a RR X rr. • What happened? • The offspring are called first generation (F1) and they were all Round. What happened to the wrinkled trait?

6. Mendel contd… • What happened to the wrinkled Mendel then crossed two offspring from the F1 generation. • Ss X Ss • In the second generation F2, the wrinkled trait shows up again. • Mendel repeated this for the other traits he studied and saw the same phenomenon.

7. Now you try it…….. • Cross a Homozygous Red parent with Homozygous blue parent. What are the offspring's: • Genotype • Phenotype Your eyes are green but his are grey and mine are brown All caused by genes…… Genotype: 100% AA __________ Phenotype: 100% RED • Cross to Heterzygous Parents. • What are the offsprings… • Genotype • Phenotype Genotype AA: Aa: aa 1 : 2 : 1 Phenotype Red : Blue 3 : 1

8. We each have genes • Found on every chromosome • They code for traits

9. You have two genes per trait, • ONE from mom • ONE from dad They’re called ALLELES!!

10. homozygous Two of the same alleles is called, homozygous (YY /Yy) Or…. Two different alleles is called, heterozygous (Yy) heterozygous

11. It’s genetics, It’s genetics: How traits are passed on

12. Phenotype expression of genes, what you look like… • These are your traits: • Color –eyes / hair • Shape- body / face

13. Genotype the genes that control characteristics Are On….. chromosomes

14. Dominance expressing one trait over another. Recessive is masked but expressed only when both alleles are recessive.

15. Autosomes 1st -22ndpair chromosome, do not determine gender, Sex Chromosomes 23rd pair –determines sex

16. Types of Inheritance • Complete Dominance • Incomplete Dominance • Codominant • Blood Type

17. COMPLETE DOMIANCE • Only Dominant & Recessive • Only 2 Phenotypes • CODOMIANCE • Both Alleles expressed equally. • Third phenotype = speckled BB- Black Bb- Black bb- White • INCOMPLETE DOMIANCE • Both Alleles blend together • Third Phenotype = new color BB- Black Bb- Speckled bb- White BB- Black Bb- Gray bb- White Animation created by Molly in Ulead Gif Animator www.promotega.org/.../inheritance_patterns.htm

18. Blood Types - Multiple Alleles and Codominance • In humans, there are four blood types (phenotypes): A, B, AB, and O. • Blood type is controlled by three alleles. A, B, O. • O is recessive, OO alleles must be present for the person to have type O. • A & B are codominant. • If you have an A allele and a B allele, their blood type is type AB • Crosses involving blood type often use an I to denote the alleles - see chart.

19. Applied Genetics How do they study genes? Uses in everyday life?

20. Karyotype • Doctors take amniotic fluid from the unborn child. (amniocentesis) • Scientist then take one cell, break it open and extract the DNA. The picture looks like this… Then they match up the homologous chromosomes to create the following picture

21. Complete Karyotpye • What is the difference??? x x Male Female Clearer view

22. Female Male

24. Applied Genetics • Determining Genotypes • Test Cross • Pedigrees

25. Testcross • Used to determine genotype of organism. • How to testcross: • Cross an individual of unknowngenotype with an individual with a known genotype. • For example: A Red Flower …is it RR or Rr? • Testcross with a known (homozygous recessive) to determine genotype. • Geno-typically what would this look like? _RR_ X ___ _Rr__ X ___ • Do the Cross…(click to see cross) or rr rr

26. Results of Test Cross _AA_ X ___ aa Aa x aa • Phenotype: • 100% Red *No matter always yields Dominant trait. • Phenotype: • 50 % White • 50% Red * Recessive white appears.

27. http://courses.bio.psu.edu/fall2005/biol110/tutorials/tutorial4_files/fig_14_6.gifhttp://courses.bio.psu.edu/fall2005/biol110/tutorials/tutorial4_files/fig_14_6.gif

28. Types of Breeding Purebred Hybrid • Keeps blood lines pure. • Selective Breeding – breeder chooses trait which is passed on. • Harmful traits appear. • Examples • Blue People • Czar of Russia • A mixing of genes. • Natural Breeding –nature determines which trait is passed on. • Dominant Trait appear thus making stronger healthier individuals. • Examples • Blake • Lab

29. Pedigree’s • Used to determine Genotypes • Shows patterns of inheritance. • Uses symbols to represent members of a family. • Male Female Unaffected • Male Female Affected • The filled in symbol represent individuals who express the trait. Blue People of Kentucky Click Picture to see Pedigree

30. Pedigree of the Fugate Family

31. The Story of Hemophilia Late in the summer of 1818, a human sperm and egg united to form a human zygote. One of those gametes, we don't know which, was carrying a newly mutated gene. A single point mutation in a nucleotide sequence coding for a particular amino acid in a protein essential for blood clotting. The zygote became Queen Victoria of England and the new mutation was for hemophilia, bleeder's disease, carried on the X chromosome. A century later, after passing through three generations, that mutation may have contributed to the overthrow of the Tsar and the emergence of communism in Russia. Victoria passed the gene on to some of her children and grandchildren, including Princess Alexandra, who married Nicholas II, Tsar of Russia, in 1894. By 1903, the couple had produced four daughters. The next year, the long awaited male heir appeared - His Imperial Highness Alexis Nicolaievich, Sovereign Heir Tsarevich, Grand Duke of Russia. From his father, the baby Alexis inherited the undisputed claim to the throne of all the Russias. From his mother, he inherited an X chromosome carrying a copy of the mutant gene for hemophilia. Soon after his birth, signs of Alexis' mutant gene appeared. At six weeks, he experienced a bout of uncontrolled bleeding and by early 1905 the royal physicians had concluded that he was suffering from hemophilia.

32. Inbreeding: creating purebreds • Marrying close relatives, as often occurred in royal families did increase the chances that recessive harmful alleles (like hemophilia) would be inherited. • Impacts of Inbreeding: • Inbreeding has caused many breeds of dogs to have harmful genetic traits. • Dalmations are often deaf, and other dog breeds have high frequencies of epilepsy, blindness, and hip displaysia.

33. BLAKE What race is Blake?

34. Labradoddle First bred in the 1970’s by Wally Conron , the Labradoodle is a very lovable dog, known for their exceptional intelligence and trainability, low to non-shedding coat, low allergy coat, and lack of doggie odor. One of the finest family pet around! A Labradoodle is a crossbred or hybriddog created by crossing the Labrador Retriever and the Standard or Miniature Poodle. Labrador Retriever Initially bred for hunting with guns, quick running, swimming, and fighting...and their sense of smell is hardly to be credited."