Punnett Squares Day 2 Complex Patterns of Inheritance BELL RINGER 5 MIN Have homework out and ready to turn in Write todays
learning target Answer this question to the right. HINT: Use a punnett square! Two parents are heterozygous for a given trait. What
percentage of the offspring of the two parents will be homozygous for the same trait? BELL RINGER 5 MIN Two parents are heterozygous for a
given trait. What percentage of the offspring of the two parents will be homozygous for the same trait? 25%
T t T TT Tt t
Tt tt Agenda Bell Ringer (5 Min) Introduction (5 Min)
Notebook Input (20 Min) Notebook Output (5 Min) The Ms. Wynn Show (30 Min) Independent Practice (15 Min) Exit Ticket (10 Min) What Happened Here? What Happened Here?
What Happened Here? What Happened Here? What Happened Here? Notebook Input Today
you write everything that is underlined. The title of your notes is: Complex Patterns of Inheritance Simple Dominance One
trait is always dominant over the other, so there are only two choices: Tall OR short Pink OR white Round OR oval BUT,
some genes are more complex. Review: Predicting Traits Punnett squares are charts that show possible gene combinations and the probability of each combination occurring.
2/21/20 12 Review: Simple Dominance Example SpongeBob
is known for his big round eyes (R), which are dominant over an oval eye shape (r). If he is heterozygous for his round eye shape and marries a homozygous recessive woman, what are the expected phenotype percentages of his kids? Lets put this into action!
Step 1: List the genotypes of the parents: Rr eyes: ____ rr Homozygous recessive eyes: ____
Heterozygous Step 2: Make a Punnett Square Heterozygous eyes: Rr Homozygous recessive: rr R r
Rr r Rr r rr rr
Step 3: Answer the question What are the expected phenotype percentages of his kids? 50% round (Rr) 50% oval (rr)
Complex Genetics Cases Incomplete dominance Phenotype of heterozygote is a blending of trait
Two capital letters are used since neither is dominant over the other Incomplete dominance
Incomplete dominance offspring show a blending of traits from parent to parent. Neither allele is completely dominant over the other. 2/21/20
19 Incomplete dominance Example: CRCR = red CWCW = white CRCW = pink
Incomplete Dominance 2/21/20 21 Incomplete Dominance A red
flower and pink flower are crossed. What are the resulting offspring phenotypes and percentages? Step 1: List the genotypes of the parents R R
C C Red flower: _______ R W C C Pink flower: _______
Incomplete Dominance Example Step 2: Make a Punnett square CR C C C
R R CR R C C R
R R W R W C C C C
C W Incomplete Dominance Example Step 3: Answer the question What are the
resulting offspring phenotypes and percentages? CR C C C R
R CR R C C R R
50% red CW CRCW CRCW 50% pink Co-dominance together Co- = _________ BOTH alleles are expressed, (no
blending) in the heterozygote Two capital letters are used since neither is dominant over the other x
Co-dominance Co-dominance 2/21/20 does not involve blending. 26
Co-dominance Example: FBFB = black feathers FBFW = black AND white feathers FWFW = white feathers
x Co-dominance Example A black rooster and a black-and-white chicken mate. What are the resulting
percentages of each possible phenotype? Step 1: List the genotypes of the parents FBFB rooster: _______ Black-and-white chicken: _______ FBFW Black
Co-Dominance Example Step 2: Make a Punnett square A black rooster B F and a black-andwhite chicken
mate. What are W the resulting F percentages of each possible phenotype? FB
FB F F B B F F
B B FBFW FBFW Co-Dominance Example Step
3: Answer the question: What are the resulting percentages of each possible phenotype? FB
FB F F B B F
B F F F W FBFW FBFW
B B 50% black 50% black-and-white Multiple Alleles
Definition: More than 2 alleles are available for a certain gene Example: Hair color (blonde, black, brown, red,
) Multiple alleles Even if more than two alleles exist in a population, any given individual can have no more than two of them: one from the mother and one from the father.
In Labrador retriever, coat color is determined by one gene with four different alleles. Five different colors result from the combinations of these alleles. 2/21/20 32
Multiple Allele Example Example: The gene for color of pigeon wings has three possible alleles: ash red, blue, and brown. Multiple Allele Example
In humans, there are 3 possible alleles for blood type: Allele IA IB i
Codes for Type A blood (make A carbohydrates) Type B blood (make B carbohydrates) Type O blood (make neither carbohydrate)
Multiple Allele Example Genotype IAIA IAi IBIB IBi IAIB ii
Phenotype Type A blood Type A blood Type B blood Type B blood Type AB blood Type O blood Multiple Allele Example
A mother with blood type A and father with blood type B take home their baby. They later discover that their child has type O blood. Did the hospital make a mistake? Step 1: List the genotypes of the parents Mother, blood type A: _________
IAIA, IAi Father, blood type B: _________ IBIB, IBi Multiple Allele Example A mother with blood type A and father
with blood type B take home their B baby. They later discover that their child has type O blood. Did the hospital make a mistake?
IA i I I I I i
i IA i ii A B B
Multiple Allele Example Step 3: Did the hospital make a mistake? 25% chance of type O blood
IA i I i B I I
I i IA i ii A B B
Incomplete dominance or Codominance?? The phenotype of the heterozygote is intermediate from the parents phenotype. 2) Two checkered (black and white) chicken are crossed. They produce offspring with three phenotypes: black, white, and checkered. 3) A red-flowered plant is crossed with a white-flowered
plant. All of the offspring are pink. 4) A cross between a purebred animal with red hairs and a purebred animal with white hairs produces and animal that has both red hairs and white hairs. 1) Notebook Output 5 MIN People are historically discriminated based on skin color. How could science educate
people to think twice about their prejudices? Who is NOT the father? THE MS. WYNN SHOW Before the show begins, answer the following
question: A mother has type O blood and a father has type AB blood. What are the possible phenotypes of their children? 50% type A blood (all IAi) 50% type B blood (all IBi)
Please, work together with your groups. Based on the information in the following slides, which man/men could be the father of the baby. Justify your answer using a Punnett Square.
Case #1 The Mother Type A Blood The Baby Type B Blood Before we look at the possible fathers, what
are the mother and babys genotypes? Mother (Type A): IAIA or IAi Baby (Type B): IBIB or IBi Possible Father #1: Sammy the Player.
Type O Blood Possible Father #2: Billy the businessman. Type AB Blood Possible Father #3: The Waiter. Type A Blood
Possible Father #4: The Cable Guy. Type B Blood Work it out!!! Sammy, you are NOT the
father! Waiter, you are NOT the father! Neither one of you have any B alleles! Two possible fathers: Billy the Businessman and the Cable Case #2
The Mother Type AB Blood The Baby Type B Blood Before we look at the possible fathers, what
are the mother and babys genotypes? Mother: IAIB Baby: IBIB, IBi Possible Father # 1: Greg the teacher Type O Blood
Possible Father #2: Anthony the Accountant Type A Blood Possible Father #3 Brad the Barista Type AB Blood
Possible Father #4 Jose the Doctor Type B Blood Work it out!!! All of you could be the fathers!
All have either a B or O allele!! Case #3 The Mother Type O Blood The Baby Type AB Blood
Before we look at the possible fathers, what are the mother and babys genotypes? Mother (Type O): Baby (Type AB): Mother: ii
Baby: IAIB Possible Father #1: The Artist. Type O Blood Possible Father #2: Guy at the club. Type AB Blood
Possible Father #3: Cabdriver. Type A Blood Possible Father #4: Jared the Flight Attendant. Type B Blood
Work it out!!! Mom, you are NOT the right mother!! They must have switched your baby at the hospital!
Mother: ii Baby: IAIB Independent Practice 15 MIN Exit Ticket EOC ATTACK! A species of jungle chicken is codominant for red and white feathers. What color would be expressed in the offspring
represented by the missing square below if T is dominant for red feathers and t is recessive for white feathers? A. Red B. Pink C. White D. Speckled ( a mix of red and white) 2/21/20
81 HOME LEARNING Simpsons Genetic Probability Worksheet
