Biology Chapter 7 and 9 Test 2.docx - Chapter 7 Linkage Recombination and Eukaryotic Gene Mapping Overview of Chapter 7 • Unlinked genes vs linked

Biology Chapter 7 and 9 Test 2.docx - Chapter 7 Linkage...

This preview shows page 1 - 9 out of 20 pages.

Chapter 7 Linkage, Recombination and Eukaryotic Gene Mapping Overview of Chapter 7: Unlinked genes vs linked genes Recombinants vs parental Detecting gene linkage Recombination frequency Coupling (Cis) vs Repulsion (Trans) Predicting offspring proportions Chi-square test for linkage Genetic map Two-Point mapping Recombination frequency vs Map distance Three-Point mapping Double Cross Overs and Gene Order Gene linkage in humans Deletion mapping Chapter 7 Notes: 1. Linked Genes Do not assort Independently a. Linked Genes are located on same chromosome Flower color & pollen shape alleles did not independently assort. Flower color & pollen shape alleles did not independently assort. Flower Color and pollen shape alleles did not independently assort. Flower color and pollen shape alleles did not independently assort Nonrecombinant Gametes Recombinant Gametes
Image of page 1

Subscribe to view the full document.

2. Linked genes segregate together more often than not 3. In 1931, Barbara McClintock and Harriet Creighton showed that crossing over was due to physical exchange between homologous chromosomes But, Crossing over can move alleles from one homologous chromosome to another
Image of page 2
4. Use testcrosses to determine percent recombination between genes 5. Linked genes segregate together and crossing over produces recombination between them a. The further apart two genes are, the greater the probability of recombination b. Recombination frequencies can be used to generate maps of relative locations of genes on chromosomes c. The “configuration” of linked genes does not affect recombination frequencies
Image of page 3

Subscribe to view the full document.

6. T and D genes are 16 map units apart 7. If you know the distance between linked genes – in map units- you can predict the percentages of each progeny Use Chi square analysis to determine whether genes are linked Alleles of unlinked genes should show 1:1:1:1 ratio of progeny in test cross of double heterozygotes Reciprocal crossing over produces equal number of both recombinant classes
Image of page 4
AaBb x aabb Genotype Experiment 1 Experiment 2 A B 16 34 a b 14 30 A b 9 16 a B 11 20 Total 50 100 AaBb x aabb
Image of page 5

Subscribe to view the full document.

8. Constructng a Genetic Map with Two – Point Testcrosses a. Must do a series of two point crosses in order to map relative positions and distances between multiple genes
Image of page 6
9. Three-Point Testcross can be used to map three linked genes
Image of page 7

Subscribe to view the full document.

a. Can map relative positions and distances between three genes from one set of progeny.
Image of page 8
Image of page 9
  • Spring '14

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Ask Expert Tutors You can ask 0 bonus questions You can ask 0 questions (0 expire soon) You can ask 0 questions (will expire )
Answers in as fast as 15 minutes