Learn about allele frequencies in populations and how they differ from genotype frequencies. [7:27]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Understand how a gene is a stretch of DNA on a chromosome. Find out about alleles in their role as versions sequence variants of a gene. [8:18]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Explain the relationship between genotypes and phenotypes in dominant and recessive gene systems
Develop a Punnett square to calculate the expected proportions of genotypes and phenotypes in a monohybrid cross
Explain the purpose and methods of a test cross
Identify non-Mendelian inheritance patterns such as incomplete dominance, codominance, recessive lethals, multiple alleles, and sex linkage

This 17-minute video lesson provides an introduction to heredity and classical genetics. It looks at dominant and recessive traits as well as heterozygous and homozygous genotypes. [Biology playlist: Lesson 14 of 71].

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Describes genotype and phenotype, and how genes are inherited.

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Describes genotype and phenotype, and how genes are inherited.

A free CK-12 account is required to view all materials.

This 25-minute video lesson looks at the Punnett square diagram in the study of genetics. It covers dihybrid crosses, independent assortment, incomplete dominance, codominance and multiple alleles. [Biology playlist: Lesson 15 of 71].

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Population genetics is the study of genetic variation in populations. This simulation allows the user to observe the frequencies of two alleles over time.

Students reinforce their knowledge that DNA is the genetic material for all living things by modeling it using toothpicks and gumdrops that represent the four biochemicals (adenine, thiamine, guanine, and cytosine) that pair with each other in a specific pattern, making a double helix. They investigate specific DNA sequences that code for certain physical characteristics such as eye and hair color. Student teams trade DNA "strands" and de-code the genetic sequences to determine the physical characteristics (phenotype) displayed by the strands (genotype) from other groups. Students extend their knowledge to learn about DNA fingerprinting and recognizing DNA alterations that may result in genetic disorders.

This animated lesson will explain how genes are inherited in pairs, one from the mother and one from the father.

This pathway includes an introduction to how genetic information is replicated and expressed to form proteins. For a deeper look at this topic, we recommend the pathways DNA Structure and Function and Genes and Proteins from the OpenStax textbook Biology for AP® Courses.

After watching video clips from the Harry Potter and the Goblet of Fire movie, students explore the use of Punnett squares to predict genetic trait inheritance. The objective of this lesson is to articulate concepts related to genetics through direct immersive interaction based on the theme, The Science Behind Harry Potter. Students' interest is piqued by the use of popular culture in the classroom.

Cross different types of peas and study the phenotype and the genotype of the offspring.

This pathway includes an introduction to the ways that gene expression is regulated in both prokaryotes and eukaryotes. For a deeper look at this topic, we recommend the pathway Gene Regulation from the OpenStax textbook Biology for AP® Courses.

This pathway explores how we inherit our phenotypes and the origin of genetic diseases.

This STEM-based poultry curriculum uses immersive learning experiences and real genetic samples for your students to dive deep in the future evolution of our food. See how environment influences heredity, and explore the evidence that suggests T. rex as our modern chicken’s and turkey’s ancestor. This unit features 4 lessons and 10 files. Lessons are aligned to NGSS.

Students randomly select jelly beans (or other candy) that represent genes for several human traits such as tongue-rolling ability and eye color. Then, working in pairs (preferably of mixed gender), students randomly choose new pairs of jelly beans from those corresponding to their own genotypes. The new pairs are placed on toothpicks to represent the chromosomes of the couple's offspring. Finally, students compare genotypes and phenotypes of parents and offspring for all the "couples" in the class. In particular, they look to see if there are cases where parents and offspring share the exact same genotype and/or phenotype, and consider how the results would differ if they repeated the simulation using more than four traits.