Please post your answers directly on the discussion board, do not upload files.

Please post your answers directly on the discussion board, do not upload files. Images should be embedded on the post (click here for instructions to embed images on a postLinks to an external site.).

Questions for group discussion:

1. Draw the cell on the right (note that the letters indicate the gene and alleles present in each chromosome, show those letters on every drawing) as it goes from the G1 phase, to the S phase, G2 and then every phase in meiosis. Indicate the main things that happen to its chromosomes at each stage (label: sister chromatids, homologous chromosomes, Meiosis I, Meiosis II, identify which cells are haploid and which are diploid). Draw it in paper and upload a photo or scan, post it as an image not as a file to the discussion post (use the image icon to upload).
   
2. Based on the diagram you drew above: A) Which events are unique to meiosis. B) The main purpose of sexual reproduction is to produce genetic variation in the offspring. Explain at least 3 ways in which meiosis promotes genetic variation. C) Explain which events in meiosis are responsible for the principle on segregation and which events are responsible for the principle of independent assortment.
3. Given what you have learned about the principle of independent assortment and how meiosis induces variation in the genetic composition of gametes, discuss the following: Some plants can reproduce asexually (by mitosis they produce structures that can break apart from the parent plant and sprout as an independent plant with the same genetic composition as the parent plant) and sexually (by meiosis, ultimately producing male and female gametes). However, many plants can do self-fertilization (male and female gametes from the same parent plant fertilize to form a zygote). Do you think that the offspring created through self-fertilization are genetic clones of the parent, just as it occurs during asexual reproduction? Explain your choice.
4. A) When predicting the phenotype of the offspring from a dihybrid cross, why is it so important that each gene is located in a different chromosome? B) You crossed a tall plant that produces purple flowers with a short plant that also produces purple flowers. Assume tall and purple flower are dominant traits. The 2165 offspring were: 100% tall plants, ¾ of the plants produced purple flowers and the remaining 1/4 of the plants produced white flowers. What were the possible genotypes of the parents?


5. For the pedigree on the right, individuals affected with the genetic condition are indicated by the shaded symbols. A) Based on this pedigree, what type of inheritance does this genetic condition have (dominant, recessive, sex-linked)? Explain. B) What is the genotype of the parents? C) What makes an allele dominant or recessive?
6. Mendel was very lucky to study traits that follow simple hereditary rules. We now know that there are multiple factors that can interfere with the expected Mendelian ratios. A) Explain 3 genetic mechanisms that can prevent Mendel’s results from being observed and B) give an example of each.

How to post images. Here are some instructions on how to upload images on Canvas:

https://lakeland.instructure.com/courses/1186804/pages/how-to-embed-an-image-in-a-discussion-post?module_item_id=13207174

Additional Practice (Optional – not required)

Problems Involving One Gene

1. In cats, long hair is recessive to short hair. A true-breeding (homozygous) short-haired male is mated to a long-haired female. What will their kittens look like?
2. Two cats are mated. One of the parent cats is long-haired (recessive allele). The litter which results contains two short-haired and three long-haired kittens. What does the second parent look like, and what is its genotype?
3. And Mr. Smith both have widow’s peaks (dominant). Their first child also has a widow’s peak, but their second child doesn’t. Mr. Smith accuses Mrs. Smith of being unfaithful to him. Is he necessarily justified? Why or why not? Work the genetics problem predicting the frequencies of the versions of this trait among their prospective children.
4. and Mrs. Jones have six children. Three of them have attached earlobes (recessive) like their father, and the other three have free earlobes like their mother. What are the genotypes of Mr. and Mrs. Jones and of their numerous offspring?
5. and Mrs. Anderson both have tightly curled hair. (The hair form gene shows incomplete dominance. There are two alleles, curly and straight. The heterozygote has wavy hair.) The Andersons have a child with wavy hair. Mr. Anderson worries this may not be his child. Is he necessarily justified? Why or why not?

Problems Involving Two Genes

1. A man with dark (dominant), curly (see problem I.5.) hair marries a woman with light, straight hair. Their daughter, who happens to have dark hair, marries a man with light, wavy hair. Answer the following questions about this dark-haired daughter and her family.
   1. Predict the phenotypic ratio among the offspring of the daughter and her husband.
   2. What is the chance that they will have a child with hair just like his or her father’s?
2. In cats, again, black color is dominant to a special, temperature-sensitive albino gene which produces cats with dark legs, faces and tails (Siamese cats, in case you don’t recognize it). A short haired (dominant) Siamese colored female is bred to a long-haired black male. They have eight kittens: 2 black, short-haired; 2 black, long-haired; 2 Siamese, short-haired; and 2 Siamese, long-haired. What were the genotypes of the two parents?

Problems Involving Genes With Multiple Alleles

1. In a particular family, one parent has Type A blood, the other has Type B. They have four children. One has Type A, one has Type B, one has Type AB, and the last has Type O. What are the genotypes of all six people in this family? The ABO blood type gene has three alleles. IA and IB are codominant; i (for Type O) is recessive to both.
2. In a recent case in Spokane, Washington, a young woman accused a soldier of being the father of her child. The soldier, of course, denied it. The soldier’s lawyer demanded that blood types be taken to prove the innocence of his client. The following results were obtained: Alleged father, Type O. Mother, Type A. Child, Type AB. The court found the soldier guilty on the basis of the woman’s remarkable memory for dates and details that apparently eliminated all other possible fathers.
   1. What are the possible genotypes for these three people?
   2. Do you agree with the court’s decision? Why or why not?
   3. After you have answered the questions I will send a peers response and you have to explain why your answers are right or wrong compared to theirs