detecting mutations- lecture 4 Flashcards
pcr primer design
-must have 2 primers, each complementary to a different dna strand
-2 primers must flank sequence of interest, but doesnt need to be precise
how does pcr work
-heat dna to separate 2 strands
-cool down and add primers to anneal to complementary sequences
-reheat and add dna polymerase to create 2 new double stranded dna molecules
—the entire cycle repeated and each time the amount of target dna doubles
what to do with the piece of amplified dna
run a gel
genotype
the set of genes possessed by an individual organism
phenotype
appearance or manifestation of a characteristic in a given organism
allele
a particular version of a gene
locus
a specified position on a chromosome, used more or less interchangeably with gene
what are restriction enzymes
restriction enzymes provide bacteria against invading viruses but cutting up the foreign dna when it enters the cell
host dna is protected from cutting by being enzymatically modified in such a way as to prevent dna cleavage
how does gel electrophoresis separate dna fragments
according to their size- larger fragments move slower through the gel
amyotrophic latera sclerosis, als
neurological decay disease
dominant allele
the outcome is the same regardless of whether the allele is homozygous or heterozygous
gain of function mutation
altered in some way the behavior of the allele
haploinsufficiency
The situation that occurs when one copy of a gene is inactivated or deleted and the remaining functional copy of the gene is not adequate to produce the needed gene product to preserve normal function
recessive allele
trait will only be expressed if an individual is homozygous for the mutant allele
ivf
introducing egg to sperm in petri dish
A term used to describe a gene when it is found in its natural, non-mutated (unchanged) form
wild type allele
how does sanger sequencing work
DNA sequencing is
the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine
homozygous
Individuals who are homozygous have 2 of the same allele. That can be either AA or aa, homozygous dominant or homozygous recessive
homozygous dominant
An individual who is homozygous dominant for a particular gene will have two dominant “A” alleles for that gene
homozygous recessive
An individual who is homozygous recessive will have the “aa” genotype, two recessive “a” alleles
heterozygous
Individuals who are heterozygous have two different alleles for a particular gene. Typically, this is represented as “Aa”
sporadic
no prior family history
familial
runs in the family
What is a chromosome?
Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA). Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique
What do chromosomes do?
The unique structure of chromosomes keeps DNA tightly wrapped around spool-like proteins, called histones. Without such packaging, DNA molecules would be too long to fit inside cells.
For an organism to grow and function properly, cells must constantly divide to produce new cells to replace old, worn-out cells. During cell division, it is essential that DNA remains intact and evenly distributed among cells. Chromosomes are a key part of the process that ensures DNA is accurately copied and distributed in the vast majority of cell divisions.
Changes in the number or structure of chromosomes in new cells may lead to serious problems. For example, in humans, one type of leukemia and some other cancers are caused by defective chromosomes made up of joined pieces of broken chromosomes.
It is also crucial that reproductive cells, such as eggs and sperm, contain the right number of chromosomes and that those chromosomes have the correct structure. If not, the resulting offspring may fail to develop properly. For example, people with Down syndrome have three copies of chromosome 21, instead of the two copies found in other people