{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

2. Lab 1 Probability & Statistics (Sept. 21-25)

2. Lab 1 Probability & Statistics (Sept. 21-25) -...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
BIOL 2040 14 DRY LAB – PROBABILITY & STATISTICS Expectations Upon completion of this lab, you should be able to: Explain what probability is and its importance Calculate chi-square. Describe the differences between the product and sum rules with respect to probability. Explain how Punnett squares show probabilities. Reading Hartwell et al., (2008) Tools of Genetics: The Chi-Square Test p128-129 (read only the boxed information) Hartwell et al., (2008) review if necessary: Punnett squares, Ch. 2; Meiosis, Ch. 4 Required Materials Two coins (any denomination). Material Covered on Quiz Material within this lab Due Hand-in assignment sheet (answers to questions 1-18 within this lab) – due at end of lab. INTRODUCTION Probability theory and its application in statistics are central to genetics research. Given a specific hypothesis, geneticists are often concerned with determining the probability of a genetic event happening (i.e., observing certain genetic data), and testing whether data are consistent with the hypothesis. Particularly in human genetics, there is interest in predicting the chance of a certain event. For example: What is the chance that a couple will have a child with Tay-Sachs disease? Are two genes found on the same chromosome (i.e., they are “linked”)? What proportion of the population is expected to be a carrier of a disease? All three of these questions require an understanding and application of probability theory. Note that these questions deal with two different ways of thinking about probability: 1) probability as a description of the relative frequency of an event ( e.g., the proportion of a population with a disease), and 2) probability as a prediction of the ‘chance’ of a certain outcome ( e.g., the chance of having a child with a disease). To illustrate probability laws, we’re going to use Punnett squares and the coin toss. Probability Lingo Typically when describing probabilities (‘chances’), we tend to use fractions, rather than percentages. E.g., ½ or 0.5, rather than 50%. If you consider that: ½ + ½ = 1, it makes sense then that the largest (maximum) probability or frequency you can have is 1 (not 100, as in percentages), and the minimum is 0.
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
BIOL 2040 15 PUNNETT SQUARE REVIEW The Punnett square, developed in the early 20th century by the geneticist R.C. Punnett (NOT Mendel, or it would be called a Mendel square, which it isn’t), can be used to easily predict the outcome of a specific cross (or mating). The first step in generating a Punnett square is to 1) determine all possible genotypes of gametes produced by both parents – remember gametes are haploid. 2) A table is then made and all the possible different gametic genotypes are listed on the two sides of the square (gametes for one parent are listed in the top row, whereas those for the other parent are listed in the leftmost column) (See Table 1.1). 3) The combination of the different gametes from the two parents can then be used to determine the genotypes of all potential offspring.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

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