Summary of Genetics - Mendelian Experiments - Lesson 2 | Don't Memorise

00:00:00 - 00:15:00

Mendelian inheritance is a type of inheritance that was first studied by Gregor Mendel. In his experiments, Mendel crossed different plants to see how certain traits were inherited. He found that when two plants are crossed, the offspring will have either purple or white flowers, depending on which allelic form of a particular gene is present. In the second example, two different allelic forms of a gene are combined, and the resulting offspring has at least one dominant and one recessive gene. Finally, pure lines are created by crossing two organisms that are homozygous for a particular trait.

• 00:00:00 Gregor Mendel's experiments laid the foundation of modern day Genetics. He observed that all the plants he grew from seeds had purple flowers, but in the next generation, some of the plants had white flowers. He concluded that there are "factors" which carry traits from one generation to the next.
• 00:05:00 In this video, genetics professor Don Kish discusses the results of Mendelian experiments, which involve crosses between different plants to see how certain traits are inherited. In the first example, Mendel found that when two plants are crossed, the offspring will have either purple or white flowers, depending on which allelic form of a particular gene is present. In the second example, two different allelic forms of a gene are combined, and the resulting offspring has at least one dominant and one recessive gene. Finally, pure lines are created by crossing two organisms that are homozygous for a particular trait.
• 00:10:00 This video explains how Mendelian inheritance works. Mendel found that when you cross two plants, the offspring will have a phenotypic (visible) ratio of three tall plants to one dwarf plant. He also found that if you cross plants from the same family, the chance of obtaining the homozygous form (having the same gene expression) is enhanced. These concepts are related to the terms genotypic ratio and phenotypic ratio.
• 00:15:00 In this lesson, we learn about Mendel's experiments and how he crossed plants to study one character at a time. We then learn about how he crosses plants and gets different ratios depending on the type of cross. Finally, we learn about dihybrid crosses and the different ratios they produce.