Lab 7Lab 7

Organism GeneticsOrganism Genetics

Lab 7: Genetics of Lab 7: Genetics of OrganismsOrganisms

OverviewOverview In this laboratory students will use living In this laboratory students will use living

organisms to do genetic crosses. They organisms to do genetic crosses. They will learn how to collect and manipulate will learn how to collect and manipulate the organisms, collect data from F1 and the organisms, collect data from F1 and F2 generations, and analyze the results F2 generations, and analyze the results from a monohybrid, dihybrid, or sex-from a monohybrid, dihybrid, or sex-linked cross.linked cross.

Pre-LabPre-Lab

Before doing this laboratory students Before doing this laboratory students should understand:should understand:

chi-square analysis of data; andchi-square analysis of data; and

the life cycle of diploid organisms useful the life cycle of diploid organisms useful in genetics studies.in genetics studies.

Drosophila melanogaster Drosophila melanogaster (wild type)(wild type)

Genetics VocabularyGenetics Vocabulary

Sex-linked-gene that is located on a sex chromosomeSex-linked-gene that is located on a sex chromosome Autosomal genes-genes located on non-sex Autosomal genes-genes located on non-sex

chromosomeschromosomes Wild typeWild type MutantsMutants Chi-squared analysis-tests the validity of a null Chi-squared analysis-tests the validity of a null

hypothesis, which states that there is no statistically hypothesis, which states that there is no statistically significant difference between the observed results of significant difference between the observed results of your experiment and the expected results. When there your experiment and the expected results. When there is little difference between the observed results and the is little difference between the observed results and the expected results, you obtain a very low chi-square expected results, you obtain a very low chi-square value; your hypothesis is supported. value; your hypothesis is supported.

Life Cycle of Fruit FliesLife Cycle of Fruit Flies

Mutants!!!!Mutants!!!!

Why are fruit flies used in Why are fruit flies used in genetic research?genetic research?

Reproduce quickly allowing easy tracking Reproduce quickly allowing easy tracking of inherited traits.of inherited traits.

Share 60% of the same genes as Share 60% of the same genes as humans.humans.

Scientists have “mapped” most of their Scientists have “mapped” most of their genes.genes.

Post-LabPost-Lab

After doing this laboratory students should be After doing this laboratory students should be able to:able to:

investigate the independent assortment of two investigate the independent assortment of two genes and determine whether the two genes genes and determine whether the two genes are autosomal or sex-linked using a multi-are autosomal or sex-linked using a multi-generation experiment; andgeneration experiment; and

analyze the data from their genetic crosses analyze the data from their genetic crosses using chi-square analysis techniques.using chi-square analysis techniques.