1 / 12

Probability & Genetics

Probability & Genetics. Genetics & Probability. Mendel’s laws: segregation independent assortment reflect same laws of probability that apply to tossing coins or rolling dice. B. B. B. BB. Bb. b. Probability & genetics.

coby
Download Presentation

Probability & Genetics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Probability & Genetics

  2. Genetics & Probability • Mendel’s laws: • segregation • independent assortment reflect same laws of probability that apply to tossing coins or rolling dice

  3. B B B BB Bb b Probability & genetics • Calculating probability of making a specific gamete is just like calculating the probability in flipping a coin • probability of tossing heads? • probability making a B gamete? 100% 50%

  4. B Bb b Probability & genetics • Outcome of 1 toss has no impact on the outcome of the next toss • probability of tossing heads each time? • probability making a B gamete each time? 50% 50%

  5. male / sperm P P PP P p P p p P p p Pp pp P female / eggs p Calculating probability Pp x Pp sperm egg offspring 1/2 x 1/2 = 1/4 1/2 x 1/2 = 1/4 + PP Pp 1/4 1/2 x 1/2 = 1/2 Pp pp 1/2 x 1/2 = 1/4

  6. P Pp p Rule of multiplication • Chance that 2 or more independent events will occur together • probability that 2 coins tossed at the same time will land heads up • probability of Pp x Pppp 1/2 x 1/2 = 1/4 1/2 x 1/2 = 1/4

  7. YyRr YyRr Yy Yy Rr Rr x x yyrr yy rr Calculating probability in crosses Use rule of multiplication to predict crosses x 1/16 ?% 1/4 1/4 x

  8. Apply the Rule of Multiplication AABbccDdEEFf x AaBbccDdeeFf AabbccDdEeFF AAxAa Aa 1/2 BbxBb bb 1/4 Got it? Try this! ccxcc cc 1 DdxDd Dd 1/2 EExee Ee 1 1/64 FfxFf FF 1/4

  9. B b Bb b B Bb 1/4 1/2 x 1/2 = 1/4 1/4 + 1/2 x 1/2 = 1/4 1/2 Rule of addition • Chance that an event can occur 2 or more different ways • sum of the separate probabilities • probability of BbxBbBb sperm egg offspring

  10. Chi-square test • Test to see if your data supports your hypothesis • Compare “observed” vs. “expected” data • is variance from expected due to “random chance”? • or is there another factor influencing data? • null hypothesis • degrees of freedom • statistical significance

  11. Any Questions??

More Related