Genetics Basics

Genetics

Definition

• The study of heredity, genes, and genetic variation
• Examines how traits are passed down from one generation to the next

Key Concepts

• Genes: segments of DNA that code for specific traits or proteins
• Genotype: an individual's genetic makeup (e.g., BB or Bb)
• Phenotype: an individual's physical and behavioral traits (e.g., blue eyes or brown eyes)
• Chromosomes: thread-like structures made up of DNA and proteins that carry genes

Mendelian Genetics

• Law of Segregation: each pair of alleles separates during gamete formation
• Law of Independent Assortment: alleles for different genes are sorted independently during gamete formation
• Punnett Square: a diagram used to predict the probability of different genotypes and phenotypes in offspring

DNA Structure and Function

• Double Helix: the twisted ladder-like structure of DNA
• Nucleotides: building blocks of DNA, consisting of a sugar, phosphate, and nitrogenous base
• Base Pairing: A-T and G-C pairings that hold the double helix together
• Replication: the process of making an exact copy of DNA
• Transcription: the process of creating a complementary RNA copy from DNA
• Translation: the process of building a protein from mRNA

Genetic Variation

• Mutations: changes in the DNA sequence
• Genetic Drift: random changes in the frequency of alleles in a population
• Gene Flow: the movement of genes from one population to another
• Natural Selection: the process by which individuals with favorable traits are more likely to survive and reproduce

Genetic Inheritance Patterns

• Autosomal Dominant: a dominant allele that will always be expressed if an individual has one copy of the allele
• Autosomal Recessive: a recessive allele that will only be expressed if an individual has two copies of the allele
• X-Linked: genes located on the X chromosome, which can result in different inheritance patterns in males and females

Genetics

Definition and Scope

• Genetics is the study of heredity, genes, and genetic variation, examining how traits are passed down from one generation to the next

Genetic Fundamentals

Genes and Chromosomes

• Genes are segments of DNA that code for specific traits or proteins
• Chromosomes are thread-like structures made up of DNA and proteins that carry genes
• Humans have 23 pairs of chromosomes, for a total of 46 chromosomes per cell

Genotype and Phenotype

• Genotype refers to an individual's genetic makeup (e.g., BB or Bb)
• Phenotype refers to an individual's physical and behavioral traits (e.g., blue eyes or brown eyes)

Mendelian Genetics

Laws of Inheritance

• The Law of Segregation states that each pair of alleles separates during gamete formation
• The Law of Independent Assortment states that alleles for different genes are sorted independently during gamete formation
• Punnett Squares are diagrams used to predict the probability of different genotypes and phenotypes in offspring

DNA Structure and Function

DNA Structure

• DNA is structured as a double helix, with a twisted ladder-like shape
• Nucleotides, the building blocks of DNA, consist of a sugar, phosphate, and nitrogenous base
• Base pairing (A-T and G-C) holds the double helix together

DNA Replication and Expression

• Replication is the process of making an exact copy of DNA
• Transcription is the process of creating a complementary RNA copy from DNA
• Translation is the process of building a protein from mRNA

Genetic Variation and Evolution

Sources of Variation

• Mutations are changes in the DNA sequence
• Genetic drift refers to random changes in the frequency of alleles in a population
• Gene flow is the movement of genes from one population to another
• Natural selection is the process by which individuals with favorable traits are more likely to survive and reproduce

Patterns of Inheritance

Autosomal Dominant and Recessive Traits

• Autosomal dominant traits are expressed when an individual has one copy of the dominant allele
• Autosomal recessive traits are expressed when an individual has two copies of the recessive allele

X-Linked Traits

• Genes located on the X chromosome can result in different inheritance patterns in males and females

Intro to genetics, covering genes, genotypes, phenotypes, and chromosomes. Understand how traits are passed down from one generation to the next.