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In our first animation of this series we learned how point mutations can edit genetic information. Here we see how duplication events can dramatically lengthen the genetic code of an individual. As point mutations add up in the duplicated region across generations, entirely new genes with new functions can evolve. In the video we see three examples of gene duplications resulting in new traits for the creatures who inherit them: the evolution of a venom gene in snakes, the evolution of leaf digestion genes in monkeys, and the evolution of burrowing legs in hunting dogs.

Explore eight different mutations with graphics, gene explanations, and phenotypic effects.

Human populations have adapted to varying intensities of sunlight with varying tones of skin coloration. The balanced interplay between melanin content and UV absorption allowed populations to successfully migrate from sub-Saharan Africa by influencing levels of two key vitamins: vitamin D and folic acid. This case study explores the evolutionary advantage of different skin tones for the human race; it also emphasizes the absence of scientific evidence for the correlation of abilities, talents, and other complex traits to skin color, and exposes certain social misconceptions linking skin color to specific traits. Although the discussion of race is not always a comfortable fit for science and biology courses, this case study uses the topic as an inherently interesting and important subject for applying basic biological concepts of DNA, the central dogma, and mutations to real world questions of physical difference and skin color. This case has been used in biology courses for non-science majors but would also be appropriate for advanced high school students.

This interrupted case is based on a genome wide association study (GWAS) that identified the genetic variation causing some inhabitants of the Solomon Islands to have blond hair. The case illustrates the connection between genotype and phenotype, and an application of Hardy-Weinberg equilibrium. The narrative focusses on John and his new roommate, Peter, from the Solomon Islands who happens to have dark skin and blond hair. Using thought-provoking questions students learn about the genetics and the biochemistry of the hair color trait and how a single genetic variation can influence phenotype. Is migration or mutation involved?  Upon completion of the activity students will know the source of the genetic variation that causes the blond hair phenomenon in the Solomon Islands and if it has any European origins. The case was written for an upper-level genetics course, but could also be adapted for introductory biology or for a genetics course for non-majors. An optional PowerPoint presentation with clicker questions is available for download from within the Answer Key.

A complete understanding of evolution requires knowledge that spans many biological sub-disciplines. However, students are often taught evolution in the context of ecological systems and isolated from genetic and cellular ones. To address this issue, we have developed case studies that track the evolution of traits from their origination in DNA mutation, to the production of different proteins, to the fixation of alternate macroscopic phenotypes in reproductively isolated populations.

SciShow explains the genetics -- and physics -- behind why blue eyes are blue, and what the future may be for the trait. Spoiler alert: Blue eyes aren't really blue! SciShow explains!

For at least 10,000 years, humans have been cultivating plants and selectively breeding them for fast growth, pest resistance, long-term survival in storage, and bigger and better fruit. We've been domesticating animals for just as long, selecting for traits that suited our needs, such as size, appearance, or even personality. For a few decades, we've also had genetic engineering methods for getting the characteristics we want in plants, animals, and microorganisms.