Genetics Chapter 1 Lecture notes

GENETICS Welcome to Bio 315 TR, 11:10 AM -12:30 PM Instructor: Dr. Suresh Nimmagadda Office hours: G83 Shineman Center T & R, 1:00-2:00 PM or by appointment The best way to communicate is via e-mail, include “Bio 315” in the subject line. Contact Information Primary Resources Course Resources- on Bb: Lecture slides, useful links, videos, quizzes and question bank Required Text: Genetics: Analysis & Principles. 6th edition. Robert J. Brooker. 2018. McGraw-Hill. Grading Lecture, 100% will comprise: 3 in-class midterms= 54% (18% for each) 1 final exam= 30% Quizzes= 12% Attendance and Participation= 4% No Make-up exam will be allowed unless you have documented absence There will be no formal extra credit available for this course Important Dates {5C22544A-7EE6-4342-B048-85BDC9FD1C3A}September 18, T Midterm Exam I October 16, T Midterm Exam II November 13, T Midterm Exam III December 11, T Final Exam (10:30 AM-12:30PM) What you can expect from me? Lecture slides will be posted two day’s before the lecture After each chapter quizzes will be available on Bb-Connect All the resources, announcements, updates on Bb site E-mails will be answered within 24h (or 48h, if sent over the weekend or holidays) You are expected to: Attending class is mandatory Timely notice of valid absences- 4 /more unexcused absence-will receive failing grade; Each day of unexcused absence will receive 0.5% reduction of attendance grade Mindful behavior in the class Manage your time-submit assignments/quizzes by the posted deadlines Traits are passed from parents to offspring Genes are units of heredity Everyone is unique and different because of genes Chapter 1: Overview of Genetics The Neolithic Era (8000-10000BC) Domestication of Plants and Animals e.g., Animals-sheep, goat, pigs, cattle, dogs, horses. Plants-wheat, barley, peas, rice, corn Artificial Selection-Desirable Traits/Characteristics to reproduce Overview of Genetics-Neolithic Era Natural Selection (1859)-Charles Darwin Mendelian Inheritance (1865)-Gregor Mendel Overview of Genetics-19th Century Word “Gene” is Coined (1909)-Wilhelm Johannsen Chromosomes Carry Genes (1911)-Thomas Hunt Morgan Genes are Made of DNA (1952)- Alfred Hershey & Martha Chase DNA Double Helix (1953)- Francis H. Crick and James D. Watson Overview of Genetics-20th Century GENOME Overview of the Human Genome Project? Formally launched in 1990 Aimed to decode our GENOME-all of the DNA found within all of our chromosomes Coordinated by the National Institutes of Health (NIH) and the Department of Energy (DOE) Carried out by scientists from around the world GENOME The completed sequence of the human genome was published in 2003 Nearly 3 billion nucleotides –ATGC Accuracy greater than 99.99% 1000 Genomes Project was launched to catalog human genetic variation Sequencing of 2,500 genomes was described in Nature in 2015 The study of the human genome provides fundamental molecular details about ourselves How many genes we have? 22,000 genes coding for protein How cells develop into complex tissue How defective genes cause disease- Cystic fibrosis, Sickle cell anemia GENOME Genetic Technologies Mammalian cloning- In 1997, Ian Wilmut and colleagues cloned the first mammal, a sheep named Dolly Mice can be made to glow green Cows, mice, goats, pigs and cats have now been cloned Genetic Technologies Genetics is centered on the study of genes The gene is classically defined as a ‘unit’ of heredity The modern definition is a segment of DNA that produces a functional product such as a polypeptide. Genes provide the blueprint that determines the traits of an organism Traits are the characteristics of an organism The Molecular Expression of Genes All cells are constructed from small organic molecules These are linked together by chemical bonds to form larger molecules Cells contain four main types of large molecules Nucleic acids Carbohydrates Proteins Lipids Living Cells are Composed of Biochemicals Nucleic Acids Cell Nucleus Containing 23 Pairs of Chromosomes Chromosomes with Genes DNA Genes are made of nucleic acid Function: Nucleic acids store and transmit hereditary information Types of nucleic acids Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA) Carbohydrates Carbohydrates include sugars and the polymers of sugars Function: to provide and store short-term chemical energy, and to provide structure Proteins Proteins account for more than 50% of the dry mass of most cells They are instrumental in almost everything organisms do Polypeptides built from the same set of 20 amino acids Proteins Determines Cell Structure and Function Proteins can Store energy-Egg Albumin Provide structure- Keratin Act as an Enzymes-Lactase Allow for movements-Myosin Transport things-Hemoglobin Act as messengers-Hormones Protect against foreign substances-Antibody Regulate genes/proteins-Transcription factors and Translation factors DNA Stores the Information for Protein Synthesis DNA Stores the Information for Protein Synthesis b) A micrograph of 46 chromosomes found in human male a) DNA is found within large structure of chromosome Gene Expression a) Gene expression at molecular level A trait is any characteristic that an organism displays We usually focus on Morphological traits Affect the appearance of the organism Example: The color of a flower There are also Physiological traits Affect the function of the organism Example: Ability to metabolize a sugar We can even identify Behavioral traits Affect the ways an organism responds to the environment Example: Mating calls of bird species The Relationship between Genes and Traits The Relationship between Genes and Traits The Relationship between Genes and Traits The Relationship between Genes and Traits The Relationship between Genes and Traits Genetic variation refers to differences in inherited traits among individuals within a population For example: In petunias, white vs. purple flowers Genetic Variation and Molecular Level Changes Changes in chromosome number Single chromosomes may be lost or gained A whole extra set of chromosomes may be inherited Genetic Variation and Molecular Level Changes The traits an individual expresses do not result from its genes alone Rather, traits are a result of the interaction between genes and the environment For example, an individual’s diet has an effect on his/her height and weight and even intelligence Traits are Governed by Genes and by the Environment The human genetic disease phenylketonuria (PKU) involves interplay between genes and environment Phenylketonuria (PKU) Humans have a gene encoding the enzyme phenylalanine hydroxylase Converts phenylalanine to tyrosine Humans with one or two functional copies of this gene can metabolize phenylalanine Humans with two copies of a rare inactive allele cannot metabolize phenylalanine Phenylalanine will thus accumulate It ultimately causes a number of detrimental effects; Mental impairment, for example Phenylketonuria (PKU) Reproduction Process During reproduction, genes are passed from parent to offspring Gregor Mendel, in the mid-19th century, provided the foundation for the science of genetics The principles of inheritance he proposed can be explained by chromosomes and their behavior during cell division Human Chromosome Composition Human Gamete Chromosome Composition Fields of Genetics Genetics is traditionally divided into three fields: Transmission Genetics Molecular Genetics Population Genetics Transmission Genetics Transmission genetics explores the inheritance patterns of traits as they are passed from parents to offspring Transmission genetics is the oldest field of genetics It examines how traits are passed from one generation to the next The conceptual framework was provided by Gregor Mendel in the 1860s Genetic determinants pass from parent to offspring as discrete units These are now termed genes Molecular Genetics It deals with how the molecular features of DNA underlie gene expression Gene organization and function Detailed analysis of DNA, RNA and proteins Molecular geneticists typically employ the genetic approach to research They study mutant genes that have abnormal function Example: Loss-of-function mutation which eliminates the function of a gene, often revealing its role in creating a trait. Population Genetics Population genetics is concerned with genetic variation and its role in evolution Population genetics deals with the genetic variation of populations and how that variation is related to the environment Population geneticists develop mathematical theories to explain the prevalence of certain alleles within populations Announcements Chapter 1, Quiz is DUE on Tue, Sep 4, 2018. Thursday’s Lecture –Chapter 2: Mendelian Inheritance