10.2 - Inheritance
Assessment statements
DCS Topic Code | Statement | Guidance |
10.2.U1 | Gene loci are said to be linked if on the same chromosome. | |
10.2.U2 | Unlinked genes segregate independently as a result of meiosis. | |
10.2.U3 | Variation 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 | Morgan’s discovery of non-Mendelian ratios in Drosophila. | |
10.2.A2 | Completion and analysis of Punnett squares for dihybrid traits. | Alleles are usually shown side by side in dihybrid crosses, for example, TtBb. |
10.2.A3 | Polygenic traits such as human height may also 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. | In representing crosses involving linkage, show genotypes as vertical pairs seperated by horizontal lines repesenting the chromosomes. |
10.2.S3 | Use of a chi-squared test on data from dihybrid crosses. |
Notes

10.2_notes.pdf |
PlayPosit
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Review PowerPoint

10.2_theoretical_genetics.ppt |