Genetics Lecture 1 DeGennaro

Population genetics

Study of the genetic composition of populations and how their gene pools change over time

20th Century Genetics( cont)

•1977 - DNA sequencing methods were developed by Frederick Sanger (1918-) and Walter Gilbert (1932-) • •1983 - Polymerase chain reaction technique was developed by Kary Mullis & others(1944-) • •1990 - Human genome project was launched • •1995 - First complete genome of living organism, Haemophilus influenzae was determined

Independent Assortment: Mendel's second law

•Alleles at different loci separate independently

Germ-Plasm Theory

•August Weismann (1834-1914) •Cut the tails of mice off for 22 consecutive generations. •Tail lengths of the descendants remained long •Ended the notion of *acquired inheritance* *Cells in the reproductive organs carry a complete set of genetic information that is passed to gametes*

Quizz: Which of the following statement is correct

All genomes are encoded in nucleic acids

iclicker: What are some of the implications of all organisms having similar genetic systems

All life forms are genetically related Research findings on one organism's gene function can often be applied to other organisms Genes from one organism can often function similarly to other organism

Model genetic organisms

An organism that is widely used in genetic studies because it has characteristics that make it particularly useful for genetic analysis

model organisms that have been the subject of intensive genetic study ( ver 2)

E. coli S. cerevisiaeterm-14 A. thaliana C. elegans D. melanogaster A. aegypti M. musculus

Which of the following are characteristics of model organisms

Easily defined characteristics

model organisms that have been the subject of intensive genetic study:

Escherichia coli, Saccharomyces cerevisiae Arabidopsis thaliana Caenorhabditis elegans Aedes aegypti Drosophila melanogaster Mus musculus,

Recent discoveries in genetic engenierring allowed humans to genetically manipulate agriculture for the first time

False (we started doing that 11,000 years ago)

Transmission genetics (Mendelian genetics)

Field of genetics that encompasses the basic principles of genetics and how traits are inherited, addresses the relationship between chromosomes and heredity

Difference between Genetics and Biochemistry

Genetics- used to explain how organisms function and how disease occurs Biochemistry- the study of chemical processes within and relating to living organisms.

Quizz: Which of the following theories of inheritance is currently considered true

Germ-plasm theory

Which of the following is NOT a model of model organism

Homo sapiens (because we have a long generational time and therefore are bad model genetic organisms)

Quizz: The 3d structure of DNA was first deciphered based on the work of

James Watson Francis Crick Maurice Wikins Rosalind Frankli

Quizz: Which scientist(s) is credited for the Law of Segregation and the Law of Independent Assortment

Mendel

Molecular genetics

Study of the chemical nature of genetic information and how it is encoded, replicated, and expressed

Quizz: Which of the following correctly describes the cell theory

The cell is the compositional and functional unit of all life

Quizz: Which of the following species is considered a model genetic organism

The worm, Caenorhabditis elegans

iclicker: Which of the following subdisciplines of genetics focuses on how an individual organism inherits and passes on its genes to the next generation.

Transmission genetics

Within the next decade or so, advances in genetics will make possible for a student in this class to have their own genome sequenced for under $1000

Yep

iclicker:All organisms share a common coding system for their genetic information. The common features of heredity imply all of the following EXCEPT THAT

all organisms will hve the same number of genes

Quizz: Within cells, genes are located on structures called

chromosomes

Gregory Johann Mendel

experiment of pea plants and build the mathematical foundation of genetics Mendel chose a good model system to study how traits were transmitted during reproduction. He used pea plants that could either self-fertilize or be crossed to another plant. By following a number of traits through many generations of pea plants, he formulated his two laws of genetics

Quizz: The complete makeup of an organism is contained in its

genome

Quizz: Which disease is a sex linked trait?

hemophilia

Quizz: Permanent, heritable changes in genetic information (DNA) are called

mutations

mutation

permanent change to DNA sequence UV damage replication errors nondisjunction in mitsosis or meiosis abnormal chromosome rearrangement

Quizz: A meassurable or observable trait or characteristic is called a:

phenotype

Segregation: Mendel's first law

•Each individual organism possesses two alleles encoding a trait • •Alleles separate when gametes are formed • •Alleles separate in equal proportions

Key concepts in genetics (cont)

•Genes come in multiple forms called ALLELES •Genes are located on the CHROMOSOME which is made of nucleic acid and proteins •Number of chromosomes vary with species (human = 46, most bacteria = 1) •Genetic material may be DNA (deoxyribonucleic acid) or RNA (ribonucleic acid)

homunculus

A tiny miniature adult,

August Weismann cut off the traits of mice for 22 consecutive generations, yet each new generation all the descendants were born with long tails. His experiment demonstrated that

Acquired characteristics are not heritable sex cells carry a complete set of genetic information that is passed to offspring

iclicker: Gregor Mendel is generally recognized as the father of genetics because

Discovered the principles of heredity by crossing different varieties of pea plants and analyzing their traits in subsequent generations

iclicker: The early 1900 was pivotal for the science of genetics because of which of the following events?

The rediscovery of Gregor Mendel's scientific discoveries Thomas Hunt Morgan's identification of the first fruit-fly mutant Walterb Sulton's proposal that chromosomes contain genes

Epigenesis

•Proposed by William Harvey (1578-1657) •An organism is derived from substance present in the egg, which differentiates into adult structures during embryonic development

Cell Theory

•Robert Brown described the cell nucleus in 1833 •Theodor Schwann and Mathis Schleiden in 1839 proposed the Cell Theory •All life is composed of cells, cells arise from pre-existing cells, and the cell is a fundamental unit of structure and function in living organisms

Common characteristics of model genetic organisms

•Short generation time, •Production of numerous progeny •The ability to carry out controlled genetic crosses •The ability to be reared in a laboratory environment •The availability of numerous genetic variants •An accumulated body of knowledge about their genetic systems

Key concepts in genetics

•The gene is the fundamental UNIT of HEREDITY •Genes are INHERITED •A complete set of genetic instruction for any organism is it GENOME •The genetic information contained in an individual is its GENOTYPE •The trait seen is the PHENOTYPE

20th Century Genetics

•Walter Sutton (1877-1916) proposed in 1902 that genes are located on the chromosome •Thomas Hunt Morgan (1866-1945) worked with fruit flies, identified first genetic mutant in 1910 (beginning of Transmission Genetics) •Ronald Fisher (1890-1962), John Haldane (1892-1964) and Sewall Wright (1889-1988) laid the foundation for Population Genetics • •James Watson (1928-) and Francis Crick (1916-) solved 3-D structure of DNA in 1953 with the data from Rosalind Franklin--> beginning of Molecular Genetics • •1973 - First Recombinant DNA experiments - revolutionized genetic research - Cloning, Genetic Engineering, Biotechnology

Model organisms drive genetic research

•We need model organisms to study genetics because there are limits to the experiments that can be done on humans •Organisms that have a short generation time are preferred, and have distinct characteristics •Many genes are conserved from yeast to humans