59 Cards in this Set
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sticky ends
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protruding single strands; free to base pair with a complementary sequence of ANY organism cut by the SAME restriction enzyme
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complete digest
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DNA has been cut at every recognition site
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vector
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DNA sequence that can enter a living cell, signal its presence and provide a means of replication for itself and the foreign DNA in it
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recombinant DNA molecule
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cutting and splicing together of vector and inserted fragment
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origin of replication
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enables it to replicated independently
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gene for antibiotic resistance
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ability to survive in a medium containing a specific antibiotic; resistance gene enables experimenters to select for propogation only those bacterial cells containing plasmid
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useful restrictions sites don't
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interrupt origin of replication or coding region of selectable marker
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BAC vectors
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harder to use than plasmid but does HUGE inserts
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genomic library
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i. Long lived collection of cellular clones that contains copies of every sequenc in the whole genome inserted into a suitable vector
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cDNA and eukaryotes
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coding sequences account for a very small percentage of genomic DNA in eukaryotes, inefficient to look in genomic libraries
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reverse transcriptase for cDNA
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a. copy its single strand of RNA into a mirror image like strand of complementary DNA
b. it then then makes complementary strand to first cDNA strand
c. this double stranded DNA copy integrates into host cell’s genome
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PCR needs
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some info on genome
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Disadvantagesof PCR
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must be <25kb
cannot serve as starting point for analysis
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sanger method
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reveal the order of base pairs in an isolated DNA molecule
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polymorphic
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locus with two or more alleles that are present in more
than 1% of a species members
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genetic variants
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alleles of a polymorphic locus
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Single nucleotide polymorphisms
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SNPs;
base positions in the genome where alternative letters of the DNA alphabet commonly distinguish some people from others; simplest and more common in non-coding regions
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SSRs
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regions of repeating two or three base long units; cause of HD; stable
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CNPs
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large regions of duplication
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ASOs (allele specific oligonucleotides)
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short oligonucleotides of
30-40 bases that hybridize to only one of the two alleles at a SNAP locus under appropriate conditions
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minisatellites
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ASOs (allele specific oligonucleotides)
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CNVs
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deletion or duplication of large blocks of genetic material of
up to 1 Mb without causing disease
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positiional cloning
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the chromosomal positions of DNA markers linked to genes defined by phenotype alone can serve as a basis for cloning those genes
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phenocopy
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indistinguishable from the inherited form of the disease yet is not caused by an inherited mutant genotype
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polygenic inheritance
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occurs when two or more genes interact in expression of a phenotype
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complex traits
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i. Penetrance and expressivity
ii. Phenocopy rather than inheritance
iii. Mutations on multiple genes
iv. Interactions of several genes
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haplotype
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a. fragments of genomes carried by our distant ancestors can be observed as blocks of DNA
i.Created over evolutionary time by accumulation of SNP variants
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synthetic segments
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-identity, order, and transcriptional direction of the genes are almost exactly the same
a. reconstruct the mouse genome by breaking the human genome into 342 fragments and pasting them together in a different order
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reshape genomes
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may affect gene activity or gene transmission by altering the position, order, or number of genes in a cell; leads to harmful genetic imbalance
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rearrangements
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reorganize the DNA sequences within one or more chromosomes
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why is heterozygosityfor deletion harmful?
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Can change GENE DOSAGE-number of times a given gene is present in the cell nucleus creating a GENETIC IMBALANCE
1. cell is also more vulnerable to subsequent mutation of that remaining copy
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when does deletion loop occur?
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prophase of meiosis 1
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Map distances in loops
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-distance between loop=0
-distance betweeen loci will be shorter because fewer crossovers can occur between them
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polytene chromsomes
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HUGE
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tandem duplications
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repeats of a region lie adjacent to each other in the same order or in reverse order
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nontandem duplications
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two or more copies of a region are not
adjacent to each other and may lie far apart on the same chromosome or on different chromosomes
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How do duplications occur?
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Duplications arise by chromosomal breakage, faulty repair, unequal crossing over, or errors in DNA replication
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duplication loop occurs when
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prophase of meiosis 1
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inversion
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half circle rotation; two double strand breaks
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Pericentric
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includes centromere
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paracentric
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exclude the centromere
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inversion loop
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allows tightest possible alignment of homologous regions; one chromosomal region rotates to conform to the similar region in the other homolog
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pericentric loop
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each recombinant chromatid will have a single centromere (normal) but will carry a duplication of one region and a deletion of a different region
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paracentric loop
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i. recombinant chromatids will be unbalanced not only in gene dosage but also in centromere number
1. Acentric fragment-lacking a centromere
2. Dicentric chromatid- two centromeres
ANY SURVIVING PROGENY WILL BE NONRECOMBINANT=BALANCER CHROMOSOMES
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INVERSIONS ACT AS
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crossover surpressors;
Use crossover suppression to create balancer chromosomes which contain multiple, overlapping inversions and a marker mutation that produces a visible dominant phenotype
ii. used to ensure the chromosome is transmitted to the next generation unchanged by recombi…
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translocation
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large scale mutations in which part of one chromosome becomes attached to a nonhomologous chromosome
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reciprocal translocation
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parts of two different chromsomes trade places
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robertsonian translocations
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a. breaks at or near the centromers of two acrocentric chromosomes
i. generates one large metacentric chromosome and one very small chromosome containing very few genes
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LINEs
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long interspersed elements
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SINEs
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short interspersed elements
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transposable elements
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a. Movement of small DNA segments from one position in the genome to another
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retroposons
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i. transpose via reverse transcription of an RNA intermediate
1. Ecodes a reverse transcriptase enzyme that copies processed retroposon RNA into complementary DNA, this DNA inserts into a new location
2. Because involvement of RNA= # of copies in genome can increase rapidly
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transposons
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i. move their DNA directly without the requirement of an RNA intermediate
1. Movement catalyzed by transposase enzymes
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nonautonomous elements
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need activity of nondeleted copies of same TE for movement
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autonomous
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move by themselves
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aneuploidy
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loss or gain of one or more chromosomes; generally lethal; better chances of survival if aneuploidy on sex chromomes
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euploid cells
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contain complete sets of chromosomes; odd number=infertile (chromosome doubling)
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autopolyploids
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all the chromosomes originally came from a single ancestral species
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allopolyploids
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i. chromosomes were derived from two different ancestral species
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BIO 325: Exam 1