Topic 10.2: Inheritance
Essential Idea: Genes may be linked or unlinked and are inherited accordingly.
At SHS, Topic 10.2 is taught in the following class unit(s):
Statements & Objectives:
10.2.U1 Unlinked genes segregate independently as a result of meiosis.
10.2.U2 Gene loci are said to be linked if on the same chromosome.
10.2.U3 Variations can be discrete or continuous.
10.2.U4 The phenotypes of polygenic characteristics tend to show continuous variation.
10.2.U5 Chi-squared tests are used to determine whether the difference between an observed and expected frequency distribution is statistically significant.
10.2.A1 Completion and analysis of Punnett squares for dihybrid traits.
10.2.A2 Morgans’s discovery of non-Mendellian ratios in Drosophilia.
10.2.A3 Polygenic traits such as human height may be influenced by environmental factors.
10.2.S1 Calculation of the predicted genotypic and phenotypic ratio of offspring of dihybrid crosses involving unlinked autosomal genes.
10.2.S2 Identification of recombinants in crosses involving two linked genes.
10.2.S3 Use of chi-squared test on data from dihybrid crosses.
10.2.NOS Looking for patterns, trends and discrepancies- Mendel used observations of the natural world to find and explain patterns and tends, Since then, scientists have looked for discrepancies and asked questions based on further observations to show exceptions to the rules. For example, Morgan discovered non-Mendellian ratios in his experiments with Drosophilia.
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