1 / 13

Punnent Squares…

Punnent Squares…. a method to determine the probability of offspring types. Punnett Squares: Shows possible traits from one parent’s genes. And the other parent’s genes. A Punnent square is like a multiplication chart!.

delu
Download Presentation

Punnent Squares…

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. Punnent Squares… a method to determine the probability of offspring types.

  2. Punnett Squares: Shows possible traits from one parent’s genes.

  3. And the other parent’s genes.

  4. A Punnent square is like a multiplication chart!

  5. Ex: Pure tall (TT) from one parent, and pure short (tt) from the other parent. Bring the letters down and over into each box in that line. T T t t

  6. Punnett Squares: Bring the letters down and over into each box in that line. Each box has the traits of a possible offspring. T T t T t t

  7. We can use a Punnett square to determine determined the probability, the chances of a particular outcome.

  8. The Bear family… • Momma Bear has brown (B) fur, but a recessive blonde (b) fur gene. • Daddy Bear has black (B) fur, and his recessive gene is brown (b). • Let’s predict the probability of having either brown or black fur in their offspring…

  9. Baby Bears…. Momma Bear BB Bb Daddy Bear Bb bb

  10. And this means? • Baby bear #1 will be BB, or pure black • Baby bear #2 will be Bb, or just as black, but carrying a recessive brown. • Baby bear #3 will be Bb, or just as black, but carrying a recessive brown. • Baby bear #4 will be bb, or pure brown.

  11. The percentages? • Brown Mama Bear and Black Daddy Bear will have a: • 25% chance of having a pure brown baby bear. • 50% chance of having a black baby bear who carries the recessive brown gene. • 25% chance of having a pure black baby bear. This means: out of 4 babies, they have the best chance of having a black bear (75%) and the least chance of having a brown bear (25%).

  12. Your activity: Materials: Your lab sheet from the “Pull a Bean” activity, paper, pencil Assignment: You will work in your science lab groups to create a Punnent square using your lab sheet data. Count up how many RR you have. Count up how many RW you have. Count up how many WW you have. Make a Punnent square and label it. Put your numbers in the correct boxes. Figure out what percentage of each type of baby bean you’ll have.

  13. THEEND Genome British Columbia, 2004 www.genomicseducation.ca

More Related