Name: _______________________________________________ Date: ______________________ Period: ________
Genetics Unit Review Worksheet Directions: IN PENCIL ONLY answer the following questions and complete the Punnett Squares and Pedigree Charts. You will be making corrections with a KEY for homework using a non blue/black pen. Use the following table to aid in determining the genotypes/phenotypes for each pattern of inheritance: What is it?
Genotypes & Phenotypes expressed
Autosomal Recessive Inheritance Explains traits or disorders that are found on autosomes (chromosome pairs 1‐ 22) Ex: PKU, Cystic Fibrosis, Albinism, Sickle Cell
Sex‐linked (recessive) inheritance Explains traits or disorders that are found on sex chromosomes‐ more specifically, the X (chromosome pair 23) Ex: color‐blindness, hemophilia
Autosomal Dominant Inheritance Explains disorders that are dominant and found on autosomes (chromosome pairs 1‐ 22) Ex: Huntington’s, Achondroplasia, DMD, FH, Neurofibromatosis
Incomplete Dominance Explains what happens when there is a blending of traits. Ex: crossing a red flower with a white flower to make a pink flower.
H = Healthy (HH or Hh)
XH = Healthy Xh = disease Males: *NO CARRIERS XHY = Healthy XhY = disease Females:
H = Disease (HH or Hh) h = healthy (hh)
Ex: Red = RR White = WW Pink = RW Ex: Blue = BB Yellow = YY Green = BY
*Hh = Carrier h = disease (hh)
*NO CARRIERS
XHXH = Healthy H h X X = Healthy (carrier) XhXh = disease
Codominance Explains what happens when neither trait is completely dominant. Both traits are EQUALLY expressed (shown). Ex: crossing a red flower (RR) with a white flower (WW) to make a flower with red and white spots (RW). Ex: Type AB blood = AB Results from crossing: Type A blood (AA or Ao) with Type B blood (BB or Bo)
Define the following: 1) Genotype: ____________________________________________________________________________________ 2) Phenotype: ___________________________________________________________________________________ 3) Allele: _______________________________________________________________________________________ 4) Punnett Square: _______________________________________________________________________________ _____________________________________________________________________________________________ 5) Pedigree Chart: ________________________________________________________________________________ _____________________________________________________________________________________________ 6) Autosomes: ___________________________________________________________________________________ 7) Sex Chromosomes: _____________________________________________________________________________
Answer the following: 8) a. In terms of genetic material, what do you inherit from your mother? ___________________________________ b. Your father? ____________________________________________
Autosomal Recessive Inheritance 9) Mendel noticed that when a tall plant and a short plant were crossed, all the offspring were tall in height. Cross a heterozygous tall plant with a short plant. Complete the Punnett square below to support your answer.
a. What are the genotypes of each parent plant? _________________
b. Which trait is dominant? ________________________ What is the probability of having a:
c. Tall pea plant? ________________
d. Heterozygous pea plant? _____________
e. Homozygous dominant plant? ______________
10) Phenylketonuria (PKU) is a recessive condition where sufferers lack an enzyme to break down phenylalanine in their diet. This condition, if left untreated, causes brain damage and retardation. Both Rita and Dexter are healthy. They have three children: Harrison (who has PKU), Cody (healthy), and Astor (healthy). Complete the Punnett square for Rita and Dexter, and a pedigree chart for all mentioned in the story).
Draw your Punnett Square below
Draw your pedigree chart below
a. List the genotypes for each person on the pedigree. What is the probability of Rita and Dexter having:
b. A healthy child? ________________________ c. A child who carries the disorder? ____________________
d. A child who has PKU? ____________________ e. TWO healthy children? ____________________________ f. A homozygous recessive child? _______________
g. If their child is a carrier of PKU, does this mean the child has the disorder? Explain: ____________________
__________________________________________________________________________________________
Sex‐Linked Inheritance 11) Hemophilia is a sex‐linked recessive disorder found on the X chromosome of males (XY) and females (XX). The allele for normal blood clotting is dominant to the allele for Hemophilia. Marge is a carrier of hemophilia and Homer is healthy. They have three children: Lisa (healthy), Bart (hemophiliac), and Maggie (healthy). Complete the Punnett square between Marge and Homer, and pedigree chart for all mentioned in the story.
Draw your Punnett Square below
Draw your pedigree chart below
a. List the genotypes for each person on the pedigree. What is the probability of Marge and Homer having a: b. Daughter with hemophilia? ________________________ c. Carrier? ________________________________
d. Son with hemophilia? ____________________________ e. Healthy child? ___________________________
12) Duchene Muscular Dystrophy (DMD) is a sex‐linked recessive disorder found on the X chromosome. Sufferers with DMD lack the protein called dystrophin. Because sufferers lack this protein, their muscle cells wear away sooner than those unaffected causing early death. Abby is homozygous recessive for DMD and Ray is healthy. Create a Punnett square and pedigree chart for all mentioned in the story.
Draw your Punnett Square below
Draw your pedigree chart below
a. List the genotypes for each person on the pedigree. What is the probability of Abby and Ray having a: b. Child with DMD? ______________ c. Girl with DMD? _____________ d. Homozygous child?_____________ e. If this couple has a boy, what are the chances that the boy will have DMD? ___________________________
Autosomal Dominant Inheritance 13) Huntington’s disease (HD) is a dominant disorder where only 1 copy of a defected allele will cause the sufferer to lose brain function and eventually die. Russ and Leslie met at a HD support clinic; both contain only one HD allele and can expect a shortened life. However, they still want to know the chances of having a child without HD. Can you help them? Create a Punnett square and pedigree chart for all mentioned in the story.
Draw your Punnett Square below
Draw your pedigree chart below
a. List the genotypes for each person on the pedigree. What is the probability of Russ and Leslie having a:
b. Healthy child? __________ c. Heterozygous child? _________ d. Homozygous dominant child? __________ 14) Bob and Charlene are both healthy. Charlene’s mother suffered from Huntington’s Disease and her father was healthy. Bob and Charlene decide to try and have a child after discussing their situation with a genetic counselor. They finally give birth to a baby girl. Create a Punnett square for Bob and Charlene, and a pedigree chart for all mentioned in the story. Draw your Punnett Square below Draw your pedigree chart below
a. List the genotypes for each person on the pedigree. b. What is the probability that their child will inherit Huntington’s Disease? ________________ c. What was the probability of Charlene having Huntington’s Disease? ________________
Incomplete Dominance Inheritance 15) Some flowers express incomplete dominance, where neither color is completely expressed. How could one create all three flower colors at one time (red, pink, white)? Support your answer with a Punnett Square. a. What are the phenotypes of EACH parent flower? __________________ What is the probability of having: b. White flowers? ___________________________________ c. Homozygous dominant flowers? _____________________ d. Heterozygous flowers? _____________________________ e. Homozygous recessive flowers? ______________________
Codominant Inheritance 16) There are 3 alleles for blood (A, B, O). A and B are both dominant, and only O is recessive. Keva has heterozygous type B blood and Kobe has type O blood. Create a Punnett Square for Keva and Kobe. a. What is Keva’s genotype? ____________ Kobe’s? ____________ What is the probability of having: b. The same genotype as Keva? ______________________ c. The same phenotype as Kobe? _____________________ d. A child with codominant blood? ____________________ e. A child with homozygous B blood? __________________ 17) There are 3 phenotypes for cattle (cow) coat. Red = RR, White = WW, and Roan = RW (which is when BOTH red and white alleles are expressed (shown) equally) A cow with a red coat mates with a cow with a roan coat. Create a Punnett Square for the red and roan coated cattle. What is the probability of having a: a. Red coated cattle? __________ b. Roan coated cattle? __________ c. White coated cattle? __________ d. Cattle with heterozygous coat? _________ e. Cattle with homozygous recessive coat? __________ g. How could one create all three cattle coat colors (red, white, roan), in a Punnett Square, at one time? _____________________________________________________________________________________________