Drosophila Lab: Exploring Genetics AP recommended lab
Two Tasks to Complete • Pre-lab Questions from 12 Recomm. Labs (link from my website) • Computer Simulated Lab: “Gene Pool” drive ***Answer Questions on a separate paper.
To Access the Lab Simulation for Drosophila • Click the “START” and choose “My Computer” • Type in the following: \\trhs_math_lang\genepool$ • Choose the “Drosophila folder” and double click the “Neo” application. • Follow the instructions and answer the guiding questions listed on the front page of your lab.
Key Parts for Drosophila Lab • Stages of Drosophila • Main Characteristics to observe (4) • Determining Male vs. Female (3) • Examine 3 Modes of Inheritance: Monohybrid: Red Eyes x Sepia Eyes Dihybrid: Eye color, Wing Sex-Linked: White eyed-female x Red eyed Male (X? X ? ) • (X ? y )
Observed Values • Table 7.2: F2 Generation -78 red-eyed females -62 white-eyed females -69 red-eyed males -73 white eyed males Expected Results: Complete #3 (both Tables) Do a Chi-square analysis. **Note: Critical values are listed in Table 7.5 on the bottom of Page 86.
Crosses to Complete for Lab #6 • Table 7.1: F1 Generation Data
F2 Generation: Sex-Linked trait Assume that the following Data was obtained and determine if it is significant or not by calculating a Chi-Square value.
Answer for First Cross X2 = (78-72)2 + (69-71)2 + (62-71)2 + (73-71)2 71 71 71 71 X2 = 0.69 + 0.06 + 1.14 + 0.06 X2 = 1.94 Degrees of freedom: (4 categories) 3 Critical Value: see Table7.3 (pg.85) 7.82 The chi-squared value is less than 7.82 Therefore:Our null hypothesis is accepted: That there is not a significant difference between the observed value and expected value. We must then accept that our results follows the expected (theoretical value).
2nd Genetic Cross • Red-Eyed: Dominant S • Sepia eyes: Recessive s • Parental cross: SS X ss • F1 Cross: Ss X Ss • F1: All Ss • F2: 3:1 (red:sepia)
Observed Values for #7 (table) Phenotype# Observed# Expected Red-Eyed 140 calc. value sepia 60 calc. Value Total: 200 offspring Complete Questions #6 & 7
Other Crosses to do • Pg 86: Green & Albino seedlings • Pg.88: Long & short winged flies **complete and calculate Chi-Square values to determine if the results are significant and acceptable (statistically valid)