Lecture 1 Flashcards
What is Genetics?
Using a manipulation of genes/genomes to study how gens function in fundamental biological processes
What do Genes do?
They encode a product that has job in the cell
What is the Operational Function of a Gene?
A gene that contain information encoding a product, usually an RNA and protein
What is the Transmission function of a Gene?
The function that ensures a gene carries information from one generation to the next
What is a Gene?
A gene is a heritable unit that corresponds to a defined, continuous stretch of DNA on a larger nucleic acid molecule and encodes a mobile gene product that is either RNA or Protein (or both)
Are Genes on a single locus?
In the vast majority of cases yes, but sometimes traits can be controlled by a gene on two different loci
What is the Transcribed Region or Transcription Unit?
The part of DNA that is copied onto RNA
Are regulatory sequenced transcribed?
Usually not
what is a Gene composed of?
The transcribed region plus all the sequences necessary for correct expression ex. regulatory sequences
What does an instructor protein do?
A protein that instructs gene to be turned on
how do Activator proteins work?
They bind to DNA and recruits the RNA polymerase that transcribes the gene
What is added after RNA is transcribed?
A poly-A tail, usually in eukaryotes.
How do Genes remain Inactivated?
A repressor protein binds to the DNA and competes with the activator protein so that a gene cannot be transcribed
What is Genomics?
The study/cataloging of entire genomes and their gene products
What is a Genome?
The complete genetic material in a somatic cell including chloroplasts and mitochondria
What is Transcriptomics
The study of the complete set of RNA produced by a genome
What is Proteomics?
The sequencing of proteins produced
What is Phylogeny?
The study of evolutionary history of organisms
Why do different organs look different despite having the same DNA?
Because they have different RNA and Proteins
What can you tell with RNA sequencing?
How many times an RNA sequence occurs
How are Genetics and Genomics different?
In research genetics will select mutants and breed them whereas transcriptomics will isolate the mRNA sequence that is active
What is Forward Genetics?
Where genes are first identified because of their mutant phenotype. They are then later mapped to the corresponding gene and is characterized by molecular/cellular/biochemical tools
What is the Concept behind Forward Genetics?
You let the animal tell you what genes are required for a process
What is the Advantage to Forward Genetics?
It is unbiased and extremely powerful because you can identify genes nobody has ever linked to the biological process you are studying
What is a disadvantage to Forward Genetics?
It is slow and identifying a mutated gene can be tricky
What is Reverse Genetics?
When you mutate the gene of your choice. You can remove the entire gene or just change specific sequences to alter/test its function
What is the Concept behind Reverse Genetics?
You want to know in which process a particular gene is involved or how a specific mutation affects the function of the gene product e.x. enzyme activity
What is the Advantage to Reverse Genetics?
IT is extremely versatile and allows you to manipulate genes with high precision
What is a disadvantage to Reverse Genetics?
It is biased, and you may knock out a gene that is not used
What is Preformationism?
The idea that there is. preformed human in the sperm that would form the next generation
How much genetic material does a child get from its parents?
50% from each parent
What are the levels of DNA structure?
Nucleotides
Singlestrand
Double helix
Chromatin
How does DNA express information?
It encodes the characteristics of an organism
What is the is the Replication function of DNA?
It can be copies
What is the Transmission function of DNA?
It is passed from parents to offspring during reproduction
What is the Variation function of DNA?
It is subject to occasional modification that result in differences between individuals
What two things does Genotype usually refer to?
1) Entire genetic information inherited by an organism (referring to all of the specific information stored in the genome)
2) The genetic information with respect to a single gene or a group of genes
What two things does Phenotype refer to?
1) The form taken by some character (or individual characters) in a specific individual
2) Any detectable manifestation of a specific genotype, regardless of weather it is morphological, behavioural , physiological or molecule
What is the Central Dogma of molecular biology?
The way DNA goes to RNA and the to Protein
What does extended phenotypes refer to?
The idea that many animals have genetic programs that force them to do certain behaviours. eg. beavers and dams
What is the Reaction Norm?
The way to describe the plasticity (flexibility) of an organism when responding to their environment
Why might genetically identical organisms have different phenotypes?
Environmental factors
What is Genetic Variation?
Describes differences among individuals within a population
What are Morphs?
Contrasting but recurring forms or types within a single population of a species
What is the source of Variation?
Mutations
What is a Mutation?
A process that introduces a lasting change into the genetic material (DNA or RNA)
How can a Mutation be passed to offspring?
If the change occurs in the germ-line
What is a Point Mutation?
A type of mutation that affects only a single nucleotide. This may cause changes in gene expression and/or affect the function fo the corresponding gene product
What is a Chromosomal alteration and changes in number?
Multiple genes are affected by a the loss, rearrangement, reattachment of a chromosome
What are the two types of mutations?
Point mutation and Chromosomal Alteration
What are the two types of variation?
Continuous and Discontinuous
What does Continuous variation refer to?
Traits for which the phenotypes change gradually e.g. Height
What is Discontinuous Variation?
Traits that fall into distinct groups e.g. eye colour
What group do Morphs and Mutants fall under?
Discontinuous variation
What are Polymorphisms?
Relatively frequent discontinuous variants in a population
What is something rare known as?
A mutant
What is the problem with labelling something as mutant?
It can be arbitrary finding the cut off, often 1%
What do Polymorphism and Mutants result from?
Occasional changes in the genetic material
What are Alleles?
Variants of a gene that exist in a population
What is a Chromosome?
A linear piece of DNA exception: bacteria chromosomes are usually circular
Who discovered that genes are carried on chromosomes?
Sutton and Boveri
Do a genes location on a chromosome ever change?
No
What is a locus?
The location of a gene on a chromosome
What dies Giemsa staining result in?
Visible bands (G-banding) used for mapping in cytogenetics
W=What is G-banding often used for?
Testing for the presence of chromosomal abnormalities
