Lecture 1 Flashcards
Genetics
Genetics uses manipulation of genes/genomes to study how genes function in fundamental biological processes
Gene
A heritable unit. usually corresponds to a locus on a usually continuous stretch of RNA or DNA. encodes a diffusible gene product
What do we mean by diffusible gene product
Mobile gene product
What are the gene products encoded by a gene?
either RNA or protein or both
Gene locus
specific place on chromosome where the gene is
What are the two functions of a gene
Operational Function
Transmission Function
Operational Function of a gene
contains information encoding a gene product (usually an RNA and a protein)
Transmission Function of a gene
a gene carries information from one generation to the next
Centromere
Middle part of chromosome
Chromatid
A “strand” of a chromosome
T/F regulatory sequences are not included in our definition of gene
False
Gene includes both regulatory sequences and the transcribed region
Genomics
The study/cataloging of entire genomes and their gene products
Genetics vs. genomics approach
Genomics: Identify genes that RESPOND to a stimulus
Genetics: identify genes that are REQUIRED for a biological process
How does the genomic approach work
Compare tissues from individuals that receives stimulus vs. those that didn’t
How does the genetic approach work
Find mutants that don’t perform the response
Forward genetics
genes are first identified because of their mutant phenotype. Later, the mutations are mapped to the corresponding gene, and the gene is then characterized by molecular/cellular/biochemical tools.
Advantage of forward genetics
Unbiased, you can identify genes no one has ever linked to the biological process you’re studying
Disadvantage of forward genetics
Slow. Identifying mutated gene can be tricky.
Reverse genetics
You mutate the gene of your choice. This approach may be used to remove the entire gene or just change specific sequences to alter/test its function.
Advantage of reverse genetics
Extremely specific and versatile, allows you to manipulate genes with high precision.
Disadvantage of reverse genetics
Biased (tests the known unknowns).
You may waste your time
The gene you “knocked out” may not have an obvious phenotype.
Tests only a single gene at a time.
Is the following forward or reverse genetics?
You are studying eye development in the mouse. After mutagenizing mice, you identify several mutant mouse strains that display a range of eye phenotypes. After identifying the genes that are mutated, you are studying how these genes relate to eye development.
Forward
Is the following forward or 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.g. enzyme activity).
Reverse
Is the following forward or reverse genetics?
You are studying immune responses in Drosophila. In a computer search, you find a gene that has some similarity to a known regulator of the anti-bacterial defense system. To test whether this new gene plays a role in immunity, you remove the entire gene and test whether the resulting flies are immune-compromised.
Reverse
Is the following forward or reverse genetics?
You let the animal “tell you” what genes are required in a specific process.
forward