Case Study Of Mendel's Laws

When trying to understand genetics Mendel 's laws are a very big part of it. Mendel 's two laws help us understand and analyze genetic crossings. In our experiment we used drosophila melanogaster flies, a common fruit fly. This was perfect to understand and visualize how the laws take effect. Mendel stated that during the process of genetic crossing; two alleles are formed which then separated to form gametes, which would appear in fertilization. In our experiment we accomplish a cross that determined different eye and body colors. By using the Chi-Square test, we were able to test our results. Our groups hypothesis stated the number of flies from the F2 generation would accommodate Mendelian Genetic Ratio of 9:3:3:1. Our Chi-Square test results

Introduction

In the 19th century Gregor Mendel accomplished pioneered the first laws of genetics after crossing peas. He conducted an experiment with pea plants. He would use a paintbrush to transfer the genetic coding from one pea plant to another, so he could know exactly who the parents were. With the end of this experiment Mendel came up with two laws; Mendel 's law of segregation, and Mendel 's law of independent assortment. Mendel crossed over purple pea flowers with white pea flowers, which gave him purple pea flowers for the first generation also called F1. Since the offspring were all purple flowers Mendel understood that the purple gene was the dominant gene. Mendel decided to cross the F1 generation with themselves. Which resulted in three purple pea flowers and one white pea flower. By using basic Punnett square, and identify the genotype as PP and the phenotype as pp. This gave Mendel the following ratio of 3:1, three purple pea flowers and one

We then allowed the larvae to hatch, and counted and recorded the total number of flies, the phenotype, and the sex. After taking down all this information this would allow us to perform a F1 cross, we made sure to examine the flies carefully since we needed virgin flies. We prepared a new vial with the a 1:1 ratio of medium and water. After recording the data of the F1 generation, and picking out the virgin flies for the crossing, and we killed of the rest of the flies using the oil method. After some time passed the F1 generation had larva in the vial. Once we noticed the larva we had to put the flies to sleep and collect the data. We then had to prepare another two new vials and medium and water. Carefully observing the flies and picking out three males and three female virgin flies to place into the new vial. Than killing of the other flies. After about a week we had the F2 generation. This was the most important generation, it was what we were looking for to allow us to observe and compare our experiment to Mendel’s experiment. We were looking for a 9:3:3:1 ratio with our flies. Using a basic Punnett square table and the crossing that we had accomplished our results should have looked like the following Punnett square.

The capital B stated the dominate allele which is brown bodies, and the lower case b states black does which is the recessive allele. The capital E stands for red eyes,