Genetics Flashcards
What impact do mutations have on the DNA fragments?
Makes them different sizes
Can cause a sequence to no longer act as a restriction site
What is restriction fragment analysis?
Examines size distribution of DNA restriction fragments cut by restriction enzymes
What are the five uses for restriction fragment analysis?
- Examine variation within individuals
- Determine relatedness of groups
- Identify genes associated with mutations
- DNA fingerprinting
- Identify carriers of genetic disorders
What regions of DNA does human fingerprinting examine?
Non coding
Highly variable
Repeated
What does the number of alleles tell you?
The number of repeats which is the size of the DNA fragment
What is the five step procedure for DNA fingerprinting?
- DNA sample is amplified using PCR
- Sample is cut with restriction enzymes
- Fragments separated by gel electrophoresis
- DNA separated into single strands and bound to surface
- Proves are used to find fragments with repeated sequences
Paternity testing
Alleles found in a child must be present in one or both parents
What are the potential problems with fingerprinting?
Contamination of sample
Inaccurate reporting
Relatives may have same alleles
What is the solution to relatives and DNA testing?
Using several different repeats and testing for variation
What are GMO’s?
Artificially modified genomes of organisms
What are the two types of modifications of GMO’s?
- Modification of existing genomes
2. Transgenic organisms
What are transgenic organisms?
Organisms with genes from two or more species combined
Example roundup ready crops
What are two genetic technologies that treat genetic disorders?
Supplying missing gene product with working copies of the gene
Gene therapy- extracting cells, infect cells, place back in patient * only works for a while
What are seven basic methods of genetic technologies?
Replication of DNA Locating nucleotide sequences Cutting and joining sections of DNA Separating pieces of DNA Pasting DNA into an organism Sequencing sections of DNA Locating sequences of DNA
What enzyme does polymerase chain reaction use?
Heat resistant DNA polymerase
What are the steps in PCR?
- Sample DNA, primers, DNA polymerase and nucleotides combined
- Heat strands to separate them
- Strands are cooled to allow primers to bind to each strand
- DNA polymerase synthesizes new strands
- Repeat
What parts of DNA can be amplified?
Small regions between the primers
What do restriction enzymes do?
Cut DNA into fragments
What are the steps of joining and cutting DNA?
Cut with restriction enzymes
Cut at restriction site
DNA ligase bonds two parts together
How do you combine DNA from different organisms?
- Must cut with same restriction enzymes
- DNA from each is mixed which allows H bonds to form
- DNA ligase forms the sugar phosphate backbone
What is gel electrophoresis?
A process to separate DNA
Draws DNA to positive charges
How is gel electrophoresis done?
- Place mixture of DNA on gel
- Electric current is applied
- DNA separates by size
- DNA is stained
What are uses for gel electrophoresis?
Identify organisms
Locate and separate genes
Sequence DNA
What are three methods of pasting DNA into organisms?
Plasmids
Viruses
Mechanical methods
What are plasmid vectors?
Small rings found in prokaryotic cells
Have same restriction sites as the chromosomal DNA
Viral vectors or viruses
Composed of nucleic acids and proteins
Reproduce in host cell
What are the two ways viruses can reproduce?
Lytic cycle- virus is copied and then breaks apart
Lysogenic- phage DNA inserts itself into chromosome and cell continues to replicate and replicates phage
What are retroviruses?
Composed of RNA
Contains reverse transcriptase which makes DNA based on RNA sequence
Allows genetic codes based on RNA to be inserted
What is a mechanical method?
DNA is physically out into cells
What is needed when determining a nucleotide sequence?
It uses PCR , normal nucleotides and modified nucleotides.
Different dyes attach to certain bases
Sugars can’t bind to phosphates which stops PCR
What are the steps for determining a nucleotide sequence?
- DNA is separated into single strands by gel electrophoresis
- Probes are added and binds strands to their complimentary strands using hydrogen bonds
- Sample is washed to remove unbound probes
- Presence of detected
What are the uses for probes?
To detect a sequence
Genetic mapping
What is the XY system ?
Males: x and y
Females: two x
What is the xo system?
Males have one x
Females have two x’s
What is the zw system?
Males have two z’s
Females have one z and one w
Males have double the DNA
Egg cell determines gender
What is the haploid diploid system?
Males are haploid
Females diploid
Males are unfertilized eggs
Example are bees
What is environmentally induced sex determination?
Males and females aren’t genetically different
Environment causes them to be one or the other
Example temp. And turtles
