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Unit: Classical and molecular genetics

Test your understanding of Mendelian genetics!


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In the 1850s, Austrian monk Gregor Mendel carried out experiments that laid the foundations of modern genetics. Learn more about the law of segregation, the law of independent assortment, and other key elements of Mendel's model.
Mendel's model forms the core of our modern understanding of inheritance. However, in the 150 years since it was first proposed, the model has been revised and extended, and these revisions are important in explaining the inheritance patterns we see around us. Learn more about variations on Mendel's model.
How did fruit flies help researchers discover that genes are on chromosomes? Find out here, and see how the chromosomal location of a gene can affect how it is inherited.
What are the consequences of genes being carried on chromosomes? Well, all sorts of interesting stuff! We can see sex linkage when genes are on X or Y chromosomes, genetic disorders when too few or too many chromosomes are inherited, and unusual inheritance patterns when our genes are in the chromosomes of mitochondria or chloroplasts.
Mendel's "heritable factors," which we now call genes, are actually regions of DNA found on chromosomes. Learn how a gene can specify a protein through the processes of transcription and translation, and how alleles are versions of a gene that have different DNA sequences.

About this unit

Have you ever been told that you have your mother's eyes or grandfather's nose? Learn why traits run in families and how they're passed on. We'll look at Mendel's model of inheritance, see how it's been revised and extended in the past 150 years, and get a sneak preview of the modern concept of a gene.