1. Hardy-Weinberg Lab Taste Testing

2. PTC  Phenylthiocarbamide Compound contains sulfur Compound contains sulfur Harmless chemical Harmless chemical  Found in Brassica family of plants Cabbages, brussel sprouts, kale Cabbages, brussel sprouts, kale Gives a slight bitterness Gives a slight bitterness

3. Tasting PTC  Dominant: Tasters Find low concentrations of PTC extremely bitter Find low concentrations of PTC extremely bitter Homozygous tasters seem to have a very low tolerance Homozygous tasters seem to have a very low tolerance Find it more bitter than heterozygous tastersFind it more bitter than heterozygous tasters Oddity: you can only taste it if it is dissolved in your own salivaOddity: you can only taste it if it is dissolved in your own saliva  Recessive: Non-tasters Report little or no taste Report little or no taste

4. How does this reflect on role of alleles?  Alleles are different versions of same gene.  Gene encodes a protein receptor for PTC Found on chromosome 7 Found on chromosome 7  Tasters have a gene that encode Proline, Alanine and Valine at positions 49, 262 and 296 Proline, Alanine and Valine at positions 49, 262 and 296  Non-tasters have a gene A, V and I at these three positions A, V and I at these three positions

5. Sodium benzoate  Poly-unsaturated fat  Used in food to inhibit microbial growth  Works best in an acidic environment

6. Relation to a person’s fave foods  PTC bitter/Sodium benzoate salty Tend to like sauerkraut, buttermilk, turnips and spinach more than average Tend to like sauerkraut, buttermilk, turnips and spinach more than average  PTC bitter/Sodium benzoate bitter Tend to dislike sauerkraut, buttermilk, turnips, spinach less than average Tend to dislike sauerkraut, buttermilk, turnips, spinach less than average

7. Most common taste groups  Ranked in order of most common combos PTC Sodium Benzoate PTC Sodium Benzoate  1. Bittersalty  2. Bittersweet  3. BitterBitter  4. TastelessSalty  5. Any other combinations

8. Lab Methods  Part I: PTC Taste/NonTaste  Step 1: Place control paper on tongue/chew a little Negative control: you shouldn’t taste anything Negative control: you shouldn’t taste anything Something to compare the other papers to… Something to compare the other papers to…  Step 2: Place PTC(blue paper) on tongue Record what you taste Record what you taste If you don’t taste anything, chew it a little and record again If you don’t taste anything, chew it a little and record again  Are you a taster or a non-taster?

9. Lab Methods…pt 1  Step 3: Record your PTC data on the board and collect all class data  Step 4: Calculate the allele frequencies and the genotype frequencies of the class

10. Lab Methods pt 2  thiourea  How many of you can taste one but not the other?

11. Lab Methods: Pt 3  Sodium benzoate