About This Chapter
What do meticulous pea plant studies performed by a nineteenth century Austrian monk have to do with a series of hypothetical flying hamster experiments? Well, we'll begin with an overview of genetics and heredity to start you off along this interesting route of study. You'll become well-grounded in notions of heritable traits, genotypes, genes, loci, alleles and phenotypes, and see what these terms really mean for living, breathing organisms.
You'll also become well-acquainted with Gregor Mendel's first and second laws of inheritance. Chromosome segregation and independent assortment are about combinations, possibilities bestowed upon subsequent generations. We'll map those possibilities with Punnett squares, teaching you how to predict genotypes and match them to phenotypes. The significance of having homologous chromosomes with alleles, or different versions of the same gene, will become clear as we examine dominant-recessive relationships in the context of homozygous and heterozygous individuals.
Of course, there are always exceptions to the rules; we'll be looking at exceptions to complete dominance and independent assortment, such as codominance, incomplete dominance, sex-limited traits, sex-linked traits and polygenic inheritance. We'll also consider what effects recombination and crossing-over can have on resulting generations. Armed with this knowledge, you'll be able to unravel the many mysteries of the hypothetical flying hamster.
1. Genetics: Heredity, Traits & Chromosomes
We view manipulation of genes in our crops and livestock as a recent development. Yet, man has been manipulating the genetic makeup of his food for thousands of years through cultivation and breeding. This lesson will begin to help you understand how genetics works.
2. Properties of Alleles
What is a dominant phenotype and how will it affect Adrian's flying hamster research? Tune in as he studies homozygous and heterozygous genotypes and the phenotypes they produce.
3. Mendel's First Law & Its Application
Genetics is a fascinating and confusing world. This lesson will delve into Gregor Mendel's First Law, or the Law of Segregation, explaining what it means and how you can use it.
4. Mendel's Second Law: The Law of Independent Assortment
Understanding how Mendel's law of independent assortment describes inheritance of genes is as easy as flipping a coin. Grab a few coins, cue up the video and see how.
5. Mendel's Dihybrid Cross Example: Practice & Ratio
Oh no! Twice the genes and sixteen genotypes - a dihybrid cross seems overwhelming to understand. Never fear though, Punnett squares will save the day!
6. Exceptions to Simple Dominance: Codominance and Incomplete Dominance
Have you ever wondered what it means if someone is a universal donor or acceptor of blood? See how genetic interactions play a key role in this trait.
7. Exceptions to Independent Assortment: Sex-Linked and Sex-Limited Traits
More men are color blind compared women. But often, not every brother, cousin or uncle in a family tree is color blind. Why not? How can genetics explain this seemingly complex inheritance pattern?
8. Crossing Over & Gene Linkage: Definition, Importance & Results
During this latest development of his flying hamster experiments, Adrian must learn about linked genes and recombinant chromosomes to unlock the mystery of the fire-breathing hamster. In this lesson, you'll look at another exception to Mendel's law of independent assortment.
9. Human Genetics: Multifactorial Traits & Model Organisms
How do we study human genetics when most traits arise from multiple genes? It's certainly more complicated that drawing a simple Punnett square. Never fear, for model organisms are here!
10. Complementary Base Pairing: Definition & Explanation
Explore the composition and structure of DNA molecules. Learn how DNA molecules are composed of four different types of nucleotides that pair with each other in a very specific, complementary manner.
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Other chapters within the Biology 101: Intro to Biology course
- Basic Terms & Skills in Biological Science
- Inorganic Chemistry Review for Biology
- Introduction to Organic Molecules & Heterotrophs
- The Nucleotide Structure of DNA & RNA
- Enzyme Function, Interactions & Regulation
- Cell Membrane Model, Components & Transport
- Cell Structure, Organelles & Organelle Functions
- Processes & Steps of DNA Replication
- Transcription, Translation & Protein Synthesis
- Types & Effects of Genetic Mutations
- Cellular Metabolism & Respiration
- Cell Growth & The Process of Cell Division
- The Musculoskeletal, Circulatory, Respiratory, Digestive & Excretory Systems
- The Nervous System & Endocrine System
- Reproduction, Development & Survival in Animals
- Ecology Principles & Community Ecology
- Evolutionary Principles & Natural Selection
- Earth's Timeline & Geological Evolution
- Taxonomic Classification & Phylogeny
- Genetic Engineering & DNA Sequencing
- Studying for Biology 101