Topic 10.2: Inheritance
- Genes may be linked or unlinked and are inherited accordingly.
Nature of science:
- Looking for patterns, trends and discrepancies—Mendel used observations of the natural world to find and explain patterns and trends. 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-Mendelian ratios in his experiments with Drosophila. (3.1)
10.2 U 1 Gene loci are said to be linked if on the same chromosome.
10.2 U 2 Unlinked genes segregate independently as a result of meiosis.
10.2 U 3 Variation can be discrete or continuous.
10.2 U 4 The phenotypes of polygenic characteristics tend to show continuous variation
10.2 U 5 Chi-squared tests are used to determine whether the difference between an observed and expected frequency distribution is statistically significant
10. 2 A 1 Morgan’s discovery of non-Mendelian ratios in Drosophila.
10.2 A 2 Completion and analysis of Punnett squares for dihybrid traits.
10.2 A 3 Polygenic traits such as human height may also be influenced by environmental factors.
10.2 S 1 Calculation of the predicted genotypic and phenotypic ratio of offspring\ of dihybrid crosses involving unlinked autosomal genes.
10.2 S 2 Identification of recombinants in crosses involving two linked genes.
10.2 S 3 Use of a chi-squared test on data from dihybrid crosses.
In The News
In The News
- The law of independent assortment was soon found to have exceptions when looking at linked genes. What is the difference between a law and a theory in science?
Alex Lee discusses Topic 10.2