Study Guide for Genetics Test #2
Study Guide for Genetics Test #2 BIOL 211
Minnesota State University, Mankato
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This 10 page Study Guide was uploaded by Katlyn Gieseke on Friday October 14, 2016. The Study Guide belongs to BIOL 211 at Minnesota State University - Mankato taught by Dr. Daniel Toma in Fall 2016. Since its upload, it has received 63 views. For similar materials see genetics in Biology at Minnesota State University - Mankato.
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Date Created: 10/14/16
Genetics Test Number 2: Chapter 5: When was the first linking of a trait to a chromosome, specifically the X chromosome? a. 1900 by Correns b. 1950 by T.H. Morgan c. 1990 by Benzer d. 1901 by McClung There is only one gene for every one chromosome. True or False? (There are thousands of genes on one chromosome) Which statement below is false? a. If the genes/traits are recombined 30% of the time, then they are 30 units away on a chromosome. b. The farther apart two genes are, the more two genes act as if they were on a different chromosome. c. If two genes are 2cM away, there is a greater amount of recombination of those genes. d. If the genes/traits are recombined 30% of the time, 70% of the offspring has a parental phenotype. The part of chromosomes that cross over are called __________. a. Chiasmata/chisma b. Genetic recombinants c. Parental tetrads d. Stertabins A tetrad is a set of four ________ that can cross over in meiosis 1. (Chromosomes) If there is 100% cross over of chromosomes, then the chromatids have 50% crossover. True or False? (Although there is never 100% crossover, remember, when replicated a chromatid refers to one of the sister chromatids which are part of the chromosomes. So is 2 of the four sister and non-sister chromatids cross over, then there is 50% chromatid cross over and since the chromatid is part of a chromosome and one chromosome is two chromatids then 2 of the two chromosomes have crossed over.) A cis configuration has ______ on one homologue and ________ on the other. a. A wild type and mutant; a mutant and a wild type b. Mutant and mutant; wild type and wild type What are the units on gene maps? a. Centimorgans (cM) b. Map units c. Percent d. All of the above + e e + + + e e Recombinant phenotype Top two and bottom two from F2 generation have parental phenotype m m e m The farther apart the genes are on a chromosome, the less recombination there is. True or False? (The farther apart the genes are, the more likely they are to cross over and become recombinants and the closer the genes are, the less likely they are to cross over. That’s why when looking at triple point crosses and trying to find the order of genes, we take the two smallest numbers as the recombinants because the gene in the middle is less likely to separate from the two other genes it is close to.) Which statement below is false about Alfred Sturtevant? a. He was a student of T.H. Morgan b. He knew Seymour Benzer c. Developed gene maps d. Did most of his work on bees and worms Gene linkage is an exception to which mendelian law? a. 1st nd e b. 2rd c. 3 d. 4th m In incomplete linkage, the genes are not far enough apart to frequently cross over. True or False? (incomplete linkage means they are far enough apart to have a detectable frequency of crossovers, while complete linkage means the genes are so close they rarely separate) Two point test cross example: Given the table below of F2 generation organisms, find the parental genotypes, the recombinants, if the parental genotypes are cis or trans, and the map distance between the two genes assuming they are linked. A T = 4583 a T = 200 A t = 187 a t = 3000 Solution: Parental genotypes: (A T) and (a t) because they have the largest number of organisms in the F2 generation Recombinants: (A t) and (a T) because they have the least amount of organisms in the F2 generation Mapdistance= Recombinants = 387 =.0486=4.86=4.86cM total numberof organism7970 e + The parents have a cis organization of genes + Triple crossover example: The table below is the F2 generation results of the combinations of three genes in an organism Genotype # of organisms + + + 179 A B C 173 + + C 52 A B + 46 A + + 22 + B C 22 + B + 4 A + C 2 What order are the genes supposed to be in on the chromosome, what is the rate of each single crossover, and calculate the coefficient of coincidence and the interference. + Solution 1. find the parent phenotype which is highest 2 numbers of individuals, then find the double cross over’s which is the two lowest numbers of individuals Pair that is Parent=+ + + compared to the d+ B + =4oss over’s=d compared to =179 A + C =2 A B C Correct order A B C 2. Look at the other crossovers and find how far apart the genes are by using recombinant over total equation. + + C =52 + + + =179 A B + =46 + 1.2cM A B C =173 Pair total=98 20.8cM=20.8% **The 1.2cM that are added to the Purple and Yellow Calculations is the addition of the double crossover** re= 6=1.2cM tot 500 =1.2% A + + =22 rec 44 = =8.8cM A + C = 2 tot 500 possibility 3. To calculate the coefficient of coincidence, one needs to take the observed crossovers (% of double crossovers) over the expected crossovers (the percent of one single crossover times the percent of the other single crossover). coefficentof coincidence=ervedcrossover= .012 =.58 Expectedcrossovers (.20) (.100) Interferance=1−coefficentof coincidence=1−.58=.42×100=42 + The ratio of non-liked genes is ______ while the ratio of linked genes is ________. a. 1:1:1:1 and 1:1 b. 1:1 and 1+1:1:1 c. 1:1:1:1 and 3:1 d. 1:1 and 9:3:3:1 If there are 1000 individuals in a population and two genes are 10cM apart, how many organisms will have each genotype produced if the parents have a trans arrangement originally. Solution A Keep in mind, this is what the parentb look like: The 4 genotypes produced are: Ab 45% (percent x total)=(.45 x 1000)= 450 individuals with Ab Recombina AB 5% (percent x total)=(.05 x 1000)= 50 individuals with AB ab 5% (percent x total)=(.05 x 1000)= 50 individuals with ab aB 45% (percent x total)=(.45 x 1000)= 450 individuals with aB Chapter 7 Are humans Protenor or Lygaeus? (Lygaeus) A protenor male is only a male if it is missing an X chromosome. True or False? (Protenor males have to be missing an X chromosome, but the missing X can sometimes be replaced with a Y chromosome to produce fertile males) e m m The Y in a lygaeus male is what makes that individual a male. True or False? (Even if there are two X’s and one Y, the individual with that genotype would still be male) When was sex determination first studied in humans? a. 20 years ago b. 50 years ago c. 80 years ago d. 100 years ago What sex chromosome related syndrome showed that the Y is nessesary to make an individual a male? a. Turner’s Syndrome b. Kleinfelter syndrome c. 47, XXX d. 48, XXXX e. 47, XYY e Kliefelter syndrome affects a sexually abnormal female with extra X’s. True or False? (Klienfelter syndrome affects males by giving them an extra Y) m Turner’s syndrome affects a sexually abnormal females with less X’s then normal. True or False? Which portion(s) of the Y chromosome below can crossover with X chromosomes? And what portion(s) of the Y chromosome determine gender? (The tips and also the tips) m e + + Nondisjuction is when________. a. Sex chromosomes don’t separate in meiosis b. Chromosomes don’t come apart in meiosis or mitosis c. When tetrads cross over d. When the Y chromosome doesn’t separate into a separate gamete If a female doesn’t form in the womb after 7 weeks, the child automatically becomes a male. True or False? (if the statement were switched around then it would be true) + e e There are more males conceived than females. True or False? (even though more males are conceived than females, there are more females that are born, and if males are bornmprematurem they are more likely to die) The body always shuts down the correct number of X’s so there is only one X active in a person. True or False? (even though there are still syndromes associated with abnormal amount of X’s, so far it has been shown that only one X is active in each cell it is called the Lyon Hypothisis) F1 + e e Gametes Gametes Who invented and researched the ratio of sex chromosomes to autosomes in drosophila? a.rT.H. Morgan b.vMax Delbruk c.sCalvin Bridges d. Ron Konopka c The srx ratio of a normal drosophila female is ____, while the sex ration of a normal drosothila male is ____. a a. 1 and 0.5 b. 0.5 and 1 Calvin Brigde’s experiment results with the determined sex ratio. (shown below are different types of drosophila cells) (Autosomes are black, sex chromosomes are red) Normal Female Normal Male Metamale ¿of X' s 2 sexratio= ¿of X ' s = =0.5 sexratio= ¿of X ' s = =0.33 sexratio=¿∈autosome pair= 21 ¿∈autosome pair 2 ¿∈autosome pair 3 Infertile male Intersex Intersex ¿of X ' s 1 ¿of X ' s 2 ¿of X ' s 3 sexratio=¿∈autosome pair= 20.5 sexratio= ¿∈autosome pair= 30.66 sexratio= ¿∈autosome pair= 40.75 Normal Female with odd # of chromosomes Metafemale ¿of X ' s 3 ¿of X' s 3 sexratio= = =1 sexratio=¿∈autosome pair= 21.5 ¿∈autosome pair 3 Chapter 9 Four main characteristics of non-mendelian heredity: Mendelian segregation ratios are absent because meiosis based segregation is not involved Reciprocal crosses give different results and the maternal phenotype is typically inherited Extra-nuclear genes cannot be mapped onto nuclear DNA genes because they are not in the nucleus with the main chromosomal DNA Non-mendelian inheritance is not affected by substituting a different nucleus in the cell Why is mom’s phenotype usually inherited instead of dad’s (maternal effect)? a. The female creates a bigger gamete b. One mating type kills the other mating type c. One mating type silences the other mating type d. All of the above Heteroplasmy is when mitochondria only comes from the mother. True or False? (Heteroplasmy is actually the mixture of two or more different mitochondria that can lead to diseases like Leder’s (due to mutations in electron transport chain) or Kearns-sayre syndrome(due to deletions of mtDNA)) The lineage of our ancestors can be tracked using the mitochondria and the y- chromosome. True or False? (mitochondria come from mom and y comes from dad. Scientists have traced human origin to Africa and named it the Out of Africa theory) In uniparental inheritance, if the gametes from both parents are the same size, then one of the parents mitochondria or chloroplasts are silenced. True or False? Non-mednelian inheritance involves a. cpDNA b. mtDNA c. viral DNA or RNA d. All of the above Go through the examples about the Limnaea coiling from the power points posted online, but from what is seen, if a male and female are crossed, the offspring will inherit the mother’s phenotype no matter what, but if they are self crossed (self fertilized) then the phenotype depends on the genotype. Here is a link that might help explain it in a different way: https://www.youtube.com/watch?v=QJvjaebdwdw What is Bicoid? a. Protein produced by mother which is put into the egg b. Turns on and off genes c. Is diffused across the cell d. Is a main component in how an organism is built e. All of the above Other important notes, Postitive interference is usually what happens and shows less crossover than expected. Negative interference is when there is more crossover then expected.
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