Genetics Basics

Each chromosome contains many genes, the basic physical and functional units of heredity. Genes are specific sequences of bases that encode instructions on how to make proteins. Credit: Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science

Genetics Basics

Have you ever wondered why you have the same eye color as your mother or the same hair color as your father? Genetics is the study of inheritance or heredity. Geneticshelps to explain how traits are passed from parents to their young. Parents pass traits to their young through gene transmission. Genes are located on chromosomes and consist of DNA. They contain specific instructions for protein synthesis.

Genetics Basics Resources

Understanding certain genetic concepts can be difficult for beginners. Below are several helpful resources that will assist in the understanding of basic genetic principles.

Gene Inheritance

• Genetic Dominance
  Learn about the differences between complete genetic dominance, codominance, and incomplete dominance.
• Mendel's Law of Segregation
  The principles that govern heredity were discovered by a monk named Gregor Mendel in the 1860's. One of these principles is now called Mendel's law of segregation.
• Mendel's Law of Independent Assortment
  This principle of heredity formulated by Gregor Mendel states that traits are transmitted to offspring independently of one another.
• Polygenic InheritancePolygenic inheritance is the inheritance of traits such as skin color, eye color, and hair color that are determined by more than one gene.
• Sex-linked TraitsHemophilia is an example of a common sex linked disorder that is an X linked recessive trait.

Genes and Chromosomes

• Chromosomes and SexIntroduction to the basics of sex determination by the presence or absence of certain chromosomes.
• Gene Mutations
  A gene mutation is any change that occurs in the DNA. These changes can be beneficial to, have some effect on, or be seriously detrimental to an organism.

• Four Cute Features Caused by Gene MutationsDid you know that cute features such as dimples and freckles are caused by gene mutations? These traits can either be inherited or acquired.
• Genetic RecombinationIn genetic recombination, genes on chromosomes are recombined to produce organisms with new gene combinations.
• Genetic Variation
  In genetic variation, the alleles of organisms within a population change. This change may result from mutation, gene flow, or sexual reproduction.
• Sex Chromosome Abnormalities
  Sex chromosome abnormalities occur as a result of chromosome mutations brought on by mutagens or problems that occur during meiosis.

Genes and Protein Synthesis

• Decoding Your Genetic Code 
  The genetic code is the information in DNA and RNA that determines amino acid sequences in protein synthesis.
• How Does DNA Transcription Work?DNA transcription is a process that involves the transcribing of genetic information from DNA to RNA. Genes are transcribed in order to produce proteins.
• Translation: Making Protein Synthesis PossibleProtein synthesis is accomplished through a process called translation. In translation, RNA and ribosomes work together to produce proteins.

Mitosis and Meiosis

• DNA ReplicationDNA replication is the process of copying the DNA within our cells. This process is a necessary step in mitosis and meiosis.

• The Cell Cycle of GrowthCells grow and replicate through an ordered series of events called the cell cycle.
• Stage-By-Stage Guide to Mitosis
  This guide to the phases of mitosis explores the reproduction of cells. In mitosis, chromosomes are duplicated and divided evenly between two daughter cells.
• Stages of MeiosisThis stage-by-stage guide to the phases of meiosis provides details about the events that occur in each of the stages of meiosis I and meiosis II.
• 7 Differences Between Mitosis and MeiosisCells divide either through the process of mitosis or meiosis. Sex cells are produced through meiosis, while all other body cell types are produced through mitosis.

Reproduction

• Gametes: The Building Blocks of Sexual ReproductionGametes are reproductive cells that unite at fertilization to form a new cell called a zygote. Gametes are haploid cells, meaning that they contain only one set of chromosomes.

• Haploid Cells: Gametes and SporesA haploid cell is a cell that contains one complete set of chromosomes. Gametes are examples of haploid cells that reproduce by meiosis.
• How Sexual Reproduction OccursSexual reproduction is a process by which two individuals produce offspring with genetic traits from both parents. It involves the union of gametes.
• Types of Fertilization in Sexual ReproductionFertilization involves the union of male and female sex cells, which results in the production of offspring with a mix of inherited genes.
• Parthenogenesis and Reproduction Without FertilizationParthenogenesis is a type of asexual reproduction that does not require the fertilization of a female egg cell. Both plants and animals reproduce in this manner.
• What Is Asexual Reproduction?In asexual reproduction, one individual produces offspring that are genetically identical to itself. Common forms of asexual reproduction include budding, regeneration, and parthenogenesis.