BIOLOGY

• Genetics is the study of how traits or characteristics are passed from one generation to another
• Genetics explores the diversity of traits within populations, emphasizing how variations in DNA sequences contribute to individual differences and the evolution of species
• Gregor Mendel is known as the Father of Modern Genetics
• Mendel experimented with pea plants for over 10 years to understand the process of heredity
• Peas were chosen for Mendel's experiments because they grow quickly, produce a large amount per generation, and have very few variations for a trait
• Mendelian Genetics Laws:

  • Law of Dominance: the presence of a dominant allele will always mask the presence of a recessive allele
  • Law of Segregation: you receive one set of genes from each parent, having two genes for each trait
  • Law of Independent Assortment: genes for different traits are sorted separately, so the inheritance of one trait is not dependent on another
• Genotype refers to an organism's genetic information, represented by a combination of two letters that stand for the alleles for a trait (BB, Bb, bb)
• Phenotype refers to an organism's physical appearance as instructed by the genotype
• Homozygous:

  • Two alleles that are the same for a trait
  • Both are capital letters or both are small letters (BB or bb)
  • Also known as Pure

  Heterozygous:

  • Two different alleles for a trait
  • A combination of capital and small letter (Bb)
  • Also known as Hybrid
• Punnet Square:

  • A tool developed by Reginald Punnett to predict genetic combinations passed from generation to generation
  • Uses the genotype of parents, assigning genotypes using the first letter of the trait
  • Capital letter represents Dominant, small letter represents recessiveness
• • Leads to variation in allele combinations and genetic diversity
• Sex-Linkage and Recombination:

  • Humans and most mammals have two sex chromosomes, X and Y, determining an individual's sex
  • Punnett Square for Sex-Linkage uses the Sex Chromosomes (X and Y) with the genotype assigned for a trait as a superscript

  Recombination:

  • Process where pieces of DNA are broken and recombined to produce new allele combinations
  • Leads to genetic diversity and is the reason behind diversity in organisms of the same species

  Crossing Over:

  • Exchange of DNA between paired homologous chromosomes during meiosis
• Sex-Linked Traits:

  • Characteristics influenced by genes on the sex chromosomes
  • X-linked if the gene is on the X chromosome, Y-linked if on the Y chromosome

  Common Sex-Linked Traits:

  1. Colorblindness: inability to see colors normally, caused by an X-linked recessive allele

  2. Hemophilia: inherited bleeding disorder due to low levels of clotting factors, caused by an X-linked recessive allele

  3. Hypophosphatemic Rickets: disorder characterized by impaired bone mineralization due to low phosphate levels, X-linked dominant trait
• Chiasmata is the site where crossing over occurs during Meiosis.
• Colorblindness occurs when the color receptors are damaged or not present at all.
• Autosomes are chromosomes that are not sex chromosomes. Also referred to as body cells.
• Punnett Square is used to predict genotype and phenotype frequencies based on given information about parents' genotypes.
• Mendelian Genetics refers to the inheritance patterns discovered by Gregor Mendel through his experiments with pea plants.
• Genetic Disorders can be caused by mutations in genes, resulting in abnormal proteins or altered gene expression.
• Genetic Variation refers to differences between individuals within a population, including variations in alleles, genes, and traits.
• Non-mendelian genetiics: Genes are not located on a single chromosome, but are distributed throughout the genome.
• Co-dominance is when two alleles are equally dominant and are expressed equally in the phenotype
• Incomplete dominance is mixed inheritance of traits from both parents.
• Multiple alleles are alleles that are present in a population. Examples include blood type.
• Sex-linked inheritance is the transmission of alleles located on the sex chromosomes.
• Hemophilia is a genetic condition wherein the blood does not clot properly.
• Polygenic inheritance is when a trait is controlled by multiple genes.
• Sex-linked inheritance occurs in the 23rd pair of chromosomes.
• How many chromosomes are there in a human cell? 46
• What is the name given to the process whereby an organism produces gametes (sex cells) with half the number of chromosomes found in body cells? Meiosis
• Uses of Recombinant DNA

  1. Medical

  2. Agriculture

  3. Industrial

  4. Environmental
• Development of Prokaryotic Life

  3.5 billion years ago
• Uses of DNA Sequencing

  1. Genomic Medicine and Personalized Healthcare

  2. Biological and Evolutionary Research

  3. Forensic Science and Criminal Investigations
• Cyanobacteria played a crucial role in the Oxygen Revolution through photosynthesis
• Gene Cloning

  1. Making multiple, identical copies of a particular piece of DNA

  2. Isolating a DNA sequence of interest to replicate it multiple times
• CRISPR-Cas 9

  1. Enables geneticists and medical researchers to edit parts of the genome by removing, adding, or altering sections of the DNA sequence

  2. Widely used in research, biotechnology, and potential therapeutic applications for treating genetic disorders
• Uses of Genetic Engineering

  • Medicine
  • Agriculture
  • Biotechnology
• Rise of Eukaryotic Life

  2 billion years ago
• Brief History of Life on Earth
• Genetic Engineering

  Also called genetic modification, a process that uses laboratory-based technologies to alter the DNA makeup of an organism