Genetics I History, terms, Punnett squares, & simple inheritance Nancy Dow Jill Hansen

1. Biology Partnership (A Teacher Quality Grant) Genetics I History, terms, Punnett squares, & simple inheritance Nancy Dow Jill Hansen Tammy Stundon January 26, 2013

2. Pre-test Q and A board What is genetics? How come some siblings look a lot alike but others don’t? Why am I the only person in my family to have blue eyes?

3. Florida Next Generation Sunshine State Standards BENCHMARK SC.912.L.16.1* Use Mendel's laws of segregation and independent assortment to analyze patterns of inheritance. (HIGH) SC.912.L.16.2* Discuss observed inheritance patterns caused by various modes of inheritance, including dominant & recessive which are simple inheritance & codominant, sex-linked, polygenic, and multiple alleles (complex inheritance). (HIGH) The February session will go into the complex inheritance.

4. Florida Next Generation Sunshine State Standards Benchmark Clarifications Students will use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance. Students will identify, analyze, and/or predict inheritance patterns caused by various modes of inheritance. Content Limits Items referring to general dominant and recessive traits may address but will not assess the P and F1 generations. Items addressing dihybrid crosses (THIS SESSION) or patterns that include codominance, incomplete dominance, multiple alleles, sex- linkage, or polygenic inheritance may assess the P and F1 generations (NEXT SESSION).

5. Florida Next Generation Sunshine State Standards Stimulus Attributes • Inheritance outcomes may be expressed in percent, ratios, or fractions. • Scenarios may refer to codominance or incomplete dominance but not both codominance and incomplete dominance. • Punnett squares may be used to predict outcomes of a cross. Response Attribute • Options may include codominance or incomplete dominance but not both (NEXT SESSION)

6. Karyotype -display of pairs of chromosomes For Humans: 23 homologous pairs; one chromosome form mom and the other from dad Autosomes are chromosomes 1-22 Chromosome pair 23 is your sex chromosomes

7. Genetics Gene - heredity code (topic) Allele – represents specific info of the gene (affect the trait which may need several genes) Dominant Allele - upper case letter Recessive Allele - lower case letter Vocabulary …Vocabulary… Vocabulary!!!! Scenarios … Scenarios … Scenarios!!!!

8. Genetics Karyotype - the display of the pair of chromosomes with highlighted alleles Phenotype - the physical appearance of the alleles Genotype - genes of an individual Bb, BB, or bb (B is the dominant allele, b is the recessive allele) Trait - term for distinguishing phenotypic features Vocabulary …Vocabulary… Vocabulary!!!!

9. INHERITANCE OF GENES Maternal chromosome pair Paternal chromosome pair Humans have 23 pairs of chromosomes (46 individual chromosomes) and, thus, two copies of each gene. Gene Maternal gamete: egg Paternal gamete: sperm Each human gamete has just one copy of each chromosome and, thus, one copy of each gene. Gametes unite during fertilization. Child inherits one set of chromosomes from each parent and, thus, two copies of each gene. ALLELES

10. What traits will be expressed? For simple inheritance, you only need ONE Dominant allele for the Dominant trait to be expressed. Naturally, the only way for a Recessive trait to be expressed is if the person has TWO Recessive alleles. Exceptions   

11. Human chromosome sheet – to practice genotypes Traits included Freckles Ability to taste Hairline Disease Rh factor Dimples Earlobes . f t H d Rh- M e f t H D Rh- M e --- --- --- --- --- --- ---

12. GeneticsMore Vocabulary Heterozygous - a dominant and a recessive allele (Bb) (also called hybrid) Homozygous dominant - two dominant alleles (BB) (also called Purebred) Homozygous recessive - two recessive alleles (bb) (also called Purebred) Only one dominant allele need to be present to be expressed

14. Punnett squares illustrate genetic crosses. • The Punnett square is a grid system for predicting all possible genotypes resulting from a cross. • The axes representthe possible gametesof each parent. • The boxes show thepossible genotypesof the offspring. • The Punnett square yields the ratio of possible genotypes and phenotypes.

15. A monohybrid cross involves one trait. • Monohybrid crosses examine the inheritance of only one specific trait. • homozygous dominant X homozygous recessive • Genotype: all heterozygous (100%) • Phenotype: all dominant (100%)

16. PUNNETT SQUARE: ALBINISM A Punnett square is a useful tool for determining the possible outcomes of a cross between two individuals. MOTHER albino homozygous aa Cross 1 (F 1) GAMETES a a FATHER pigmented homozygous AA A Aa Aa GAMETES A Aa Aa Genotype Phenotype OFFSPRING All heterozygousAa All pigmented

17. If you cross a heterozygous with a heterozygous (Ff X Ff) • What is the genotypic ratio of the offspring? • 1:2:1 homozygous dominant: heterozygous: homozygous recessive; (25%:50%:25%) • What is the phenotypic ratio of the offspring? • 3:1 dominant: recessive (75%:25%)

18. MOTHER pigmented heterozygous Aa Cross 2 (F2) GAMETES A a FATHER pigmented heterozygous Aa A AA Aa GAMETES Your genotype and phenotype results are presented separately a Aa aa Genotype Phenotype OFFSPRING 1/4 homozygous dominant AA 3/4 pigmented 3:1 RATIO 2/4 heterozygous Aa 1/4 homozygous recessive aa 1/4 albino

19. If you cross a heterozygous with homozygous recessive • (Ff X ff) • What is the genotypic ratio? • 1:1 heterozygous: homozygous recessive • What is the phenotypic ratio? • 1:1 dominant: recessive

20. A testcross is a cross between an organism with an unknown genotype and an organism with the recessive phenotype Why use the recessive phenotype to test an unknown?

21. Probability = number of ways a specific event can occur number of total possible outcomes Heredity patterns can be calculated with probability. • Probability is the likelihood that something will happen. • Probability predicts an average number of occurrences, not an exact number of occurrences. • Probability applies to random events such as meiosis and fertilization.

22. GENETICS AND PROBABILITY IF… The mother is albino, and the father is heterozygous THEN… There is a 100% chance that the mother’s egg will carry the recessive a allele and a 50% chance that a sperm will carry the recessive a allele aa Aa 100% 50% a a A a AND… 0.5 or 50% chance the offspring will be albino. 1.0 0.5 = × Multiply the two components together to determine the overall probability. aa

23. Goat genetics

24. A Dihybrid cross involves two traits. • Mendel’s dihybrid crosses with heterozygous plants yielded a 9:3:3:1 phenotypic ratio. • Mendel’s dihybrid crosses led to his second law,the law of independent assortment. • The law of independent assortment states that allele pairs separate independently of each other during meiosis.

25. Dihybrid Cross:a cross that shows the possible offspring for two traits Coat Texture: R: Rough r: Smooth Fur Color: B: Black b: White In this example, we will cross a heterozygous individual with another heterozygous individual. Their genotypes will be: BbRr x BbRr

26. Dihybrid Cross BbRr x BbRr First, you must find ALL possible gametes that can be made from each parent. Remember, each gamete must have one B and one R. You will combine your genotype and phenotype results (heterozygous fur color)

27. Dihybrid Cross BbRr x BbRr Possible gametes: BR Br bR br Next, arrange all possible gametes for one parent along the top of your Punnett Square, and all possible gametes for the other parent down the side of your Punnett Square…

28. BR Br bR br BR Br bR br Dihybrid Crosses:a cross that shows the possible offspring for two traits BbRr x BbRr Fur Color: B: Black b: White Coat Texture: R: Rough r: Smooth Then, find the possible genotypes of the offspring

29. BR Br bR br BR BBRR BBRr BbRR BbRr Br BBRr BBrr BbRr Bbrr bR BbRR BbRr bbRR bbRr br BbRr Bbrr bbRr bbrr Dihybrid Crosses:a cross that shows the possible offspring for two traits BbRr x BbRr Fur Color: B: Black b: White Coat Texture: R: Rough r: Smooth

30. BR Br bR br BR BBRR BBRr BbRR BbRr Br BBRr BBrr BbRr Bbrr bR BbRR BbRr bbRR bbRr br BbRr Bbrr bbRr bbrr How many of the offspring would have a black, rough coat? How many of the offspring would have a black, smooth coat? How many of the offspring would have a white, rough coat? How many of the offspring would have a white, smooth coat? Fur Color: B: Black b: White Coat Texture: R: Rough r: Smooth

31. BR Br bR br BR BBRR BBRr BbRR BbRr Br BBRr BBrr BbRr Bbrr bR BbRR BbRr bbRR bbRr br BbRr Bbrr bbRr bbrr How many of the offspring would have black, rough coat? How many of the offspring would have a black, smooth coat? How many of the offspring would have a white, rough coat? How many of the offspring would have a white, smooth coat? Phenotypic Ratio 9:3:3:1 Fur Color: B: Black b: White Coat Texture: R: Rough r: Smooth

32. More practice…work within your quad Selected Traits in Cats – Study this table then determine the crosses below Show the results of the following crosses; give the info for the amount of genotypes/phenotypes 1. Heterozygous short hair and Heterozygous short hair 2. Heterozygous tabby and stripeless 3. Colorpoint and homozygous normal 4. Homozygous short homozygous colorpoint and Homozygous long homozygous normal

33. 15 minutes!!

34. Heredity – biological means of obtaining your genes Theory of Blending Inheritance – people up through the 1800s believed that people are a blending mixture of the mom and dad - support – facial features appear - But you are not an average of your parents – not an average of their height, hair color, eye color, etc.

35. MENDEL’S RESEARCH APPROACH Gregor Mendel (1822–1884) Three features of Mendel’s methodical research were critical to its success. THE ‘FATHER OF GENETICS’. 1800s A monk in modern day Czech republic. He was the first to apply math to inheritance, however, he did not know about DNA. His work is the mechanism that supports Darwin’s Natural Selection Theory.

36. Why was Mendel so successful? 1. Preliminary investigations were carried out to obtain familiarity with the experimental organism. 2. All experiments were carefully planned. 3. Meticulous care was taken in carrying out all techniques. 4. Accurate records were kept of all the results. 5. Sufficient data were obtained to have statistical significance. As Mendel stated, "The value of utility of any experiment are determined by the fitness of the material to the purpose for which it is used."

37. DOMINANT AND RECESSIVE TRAITS Mendel crossed true-breeding purple-flower plants with true-breeding white-flower plants. 1 D r True-breeding purple-flower plant True-breeding white-flower plant Studied pea plants and their reproduction • Forced cross pollination • Isolated certain traits (color, height)

38. Why did he need to “force” cross pollination? How to plants do this naturally? What is a vector?

39. DOMINANT AND RECESSIVE TRAITS 1 Mendel crossed true-breeding purple-flower plants with true-breeding white-flower plants. ‘P’ OR PARENTAL GENERATION True-breeding purple-flower plant True-breeding white-flower plant The purple-colored flower is the dominant trait, while the white-colored flower is a recessive trait. All offspring have purple flowers. F 1 OR FILIAL GENERATION 2 Then, Mendel crossed two of the purple-flower offspring.

40. DOMINANT AND RECESSIVE TRAITS All offspring have purple flowers. The purple-colored flower is the dominant trait, while the white-colored flower is a recessive trait. Then, Mendel crossed two of the purple-flower offspring. 2 Most offspring have purple flowers, but some have white flowers. F 2 GENERATION  The recessive trait for the white-colored flower must have been lurking in the previous generation, even though it is not visible.

41. MENDEL’S 2 LAWS: 1ST LAW : LAW OF SEGREGATION According to Mendel’s law of segregation, only one of the twoalleles for a gene is put into a gamete. At fertilization, offspring receive from each parent one allele for each gene. Two different alleles (white, purple) for the same gene (flower color) Heterozygous pea plant Heterozygous pea plant MEIOSISEachgamete gets one copy of each gene.

42. 1. MENDEL’S LAW OF SEGREGATION FERTILIZATION Each fertilized egg gets two copies of each gene. Homozygous recessive Heterozygous Heterozygous Homozygous dominant A PUNNETT SQUARE IS A TOOL USED TO SHOW THE PROBABILITY OF THE OFFSPRING FROM FERTILIZATION

43. MENDEL’S LAW OF INDEPENDENT ASSORTMENT Mendel’s law of independent assortment states that one trait does not influence the inheritance of another trait. MOTHER albino homozygous aa dimpled chin homozygous DD Cross 1 GAMETES a a D D FATHER pigmented homozygous AA non-dimpled chin homozygous dd A d Aa Aa Dd Dd GAMETES A d Aa Dd Aa Dd OFFSPRING Genotype Phenotype All heterozygous Aa All pigmented All heterozygous Dd All dimpled chin  In this example, having a dimpled chin does not affect which alleles are inherited for skin pigmentation.

44. MENDEL’S LAW OF INDEPENDENT ASSORTMENT Mendel’s law of independent assortment states that one trait does not influence the inheritance of another trait. MOTHER pigmented heterozygous Aa dimpled chin heterozygous Dd Cross 2 GAMETES A a D D FATHER pigmented heterozygous Aa dimpled chin heterozygous Dd A D AA Aa DD Dd GAMETES aA d Aa Dd aa dd OFFSPRING Genotype Phenotype 1/4 homozygous dominant AA 1/4 homozygous dominant DD 3/4 pigmented 3/4 dimpled chin 2/4 heterozygous Aa 2/4 heterozygous Dd 1/4 homozygous recessive aa 1/4 homozygous recessive dd 1/4 albino 1/4 non-dimpled chin

45. Investigating Genetics Corn Lab

46. http://www.genome.gov/ Tons of activities… from the Human Genome Project. http://learn.genetics.utah.edu/content/begin/tour/ Interactive activities! http://www.sciencesupport.net/geneticstutorial.html http://biology.clc.uc.edu/courses/bio105/geneprob.htm - A case problem

47. Follow up • Q & A • Post Test