(6 points) Compare and contrast mitosis and meiosis (include at least 3 comparisons and 3 differences).
Both mitosis and meiosis are usually associated the cytokinesis
In both processes, end result is usually production of daughter cells from the parent cell
The fundamentals in both processes are the same in that there is breakdown of nuclear membrane, genetic material separation into two groups, cell division and eventually the nuclear membrane in the cells reform
Differences
In meiosis, there are two rounds involved in genetic separation while in mitosis there is only one round.
In meiosis, there is separation of homologous chromosomes resulting to genetically non-identical daughter cells while in mitosis the formed daughter cells are identical and same as parent cells.
Purpose of meiosis is for gametes production in sexual reproduction while purpose of mitosis is for cell growth and regeneration in asexual reproduction.
(15 points) A woman who is a carrier for cystic fibrosis has children with a man that has cystic fibrosis.
What are the parental genotypes?
Let C represent Normal allele and c represent cystic fibrosis allele.
Father genotype is cc
Mother genotype is Cc
What F1 phenotypic and genotypic ratios are produced from this cross? (Show your Punnett Square)
Mother
Father
F1 phenotypic ratio will be 2 Carriers : 2 offspring with CF
c. Diagram the F2 results. (Show your Punnett Square).
Mother
Father
(9 points) R codes for red flower color and r codes for white flower color.
What color would Rr be if R has complete dominance?
Red
What color would Rr be if R and r are codominant?
Pink
What color would Rr be if R has incomplete dominance?
Pink
(15 points) Red-green colorblindness is an X-linked recessive mutation. A colorblind female has children with a normal male.
What are the parental genotypes? (Hint: the sex of the parent is important)
Let C represent Normal for colour-blindness allele while c represents color-blindness
Father= XCY
Mother=XcXc
b. What F1 phenotypic and genotypic ratios are produced from this cross? (Show your Punnett Square)
Mother
Father
F1 genotypic ratio will be 2 XCXc : 2 XcY
F1 phenotypic ratio will be 2 carrier females : 2 color-blind males
(5 points) In a dihybrid cross between RrTt and RRtt, what are the genotype and phenotype ratios of the offspring, assuming R and T are dominant? R codes for round seed, while r codes for wrinkled seed. T codes for tall height, while t codes for short height. (Show your Punnett Square). Hint: Do the Punnett Square for each trait separately and then combine them using the branch diagram as shown in Figure 3.11
Mother
Father
Mother
Father
Phenotypic ratio 8 rounded and tall offsprings : 8 rounded and short offsprings
(15 points) The pedigree below traces the inheritance of alkaptonuria, a biochemical disorder. Affected individuals, indicated here by the filled-in circles and squares, are unable to break down a substance called alkapton, which colors the urine and stains body tissues.
Does alkaptonuria appear to be caused by a dominant or recessive allele? Explain.
It is caused by recessive allele. If it were caused by dominant allele, all F1 offspring would have been normal according to this pedigree.
What is George’s phenotype?
normal for alkaptonuria disease.
Is it possible for Daniel to have a child with alkaptonuria? Explain.
Yes, it is possible. This is due to the fact the disease is caused by recessive allele and a male can only be normal or sufferer whereas female can be normal, carriers or sufferers. From this pedigree, Tina is either normal or a carrier, concluding that it is possible for Daniel to have a child with alkaptonuria.
How would knowing the pattern of inheritance influence the treatment plan for this disease?
Understanding the pattern of inheritance is important in the treatment plan for this disease as it shows whether the disease is caused by recessive or dominant allele and the chances that an offspring is likely to get it. Therefore, with this pattern genotypes of future offsprings can be determined and earlier precautions including treatments can be administered.
(10 points) Mary has type A blood and her husband (John) has type B blood. John's parents both had type AB. Mary and John have three children, one with type A, one with type AB, and one with type B. Relatives suspect that one of the children was adopted.
What are Mary and John's blood genotypes?
John blood genotype is BB
Mary genotype is AO
Which child was adopted? Explain your answer.
Punnet squares for the first and second test crosses
Mary
John
Mary
John
There is no blood group AA or AO.
