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56 Cards in this Set
- Front
- Back
What are Alleles?
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Alternative forms of a genetic locus
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How do we inherit alleles from our parents?
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1 from each parent for each gene, so we get 2 total alleles.
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What are autosomes?
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Chromosomes not involved in sex determination.
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How many autosomes are in the human genome?
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44 (22 pairs)
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Don't humans have 46 chromosomes?
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Yes, the other two are sex Ch's
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What does diploid refer to?
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A complete set of 2 copies of DNA chromosomes, one from each parent
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What is a Gene?
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An ordered sequence of nucleotides located in a particular position, on a particular chromosome, that encodes a specific functional product.
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What is a Genotype?
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The genetic complement that an organism inherits from its parents.
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What does genotype mean when you're talking about 1 gene?
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The particular allelic complement that is at that locus.
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What is Haploid?
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A single set of chromosomes, which is what is in gametes (oogonia, spermatogonia).
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What does Heterozygous mean?
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A person has 2 different alleles at one locus on paired chromosomes.
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What does homozygous mean?
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A person has the same allele at one locus on paired chromosomes.
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What are paired chromosomes called?
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Homologous chromosomes
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What is a locus?
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The position of a gene on a chromosome.
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What is a marker?
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An identifiable physical location on a chromosome whose inheritance can be monitored.
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What are 2 examples of markers?
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-Genes
-RFLPS |
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What is a phenotype?
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The manifold biological appearances of an organism.
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Can genotype change through an organisms lifespan? Phenotype?
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Genotype, no
Phenotype, yes |
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What is Polymorphism?
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The difference in DNA sequences among individuals
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What would be a useful polymorphism for genetic linkage analysis?
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Genetic variations occurring in more than 1% of the population.
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What is a gamete?
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Haploid set of one full set of parent's DNA combined and paired into one set of 23 chromosomes
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How many chromosomes do humans have?
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46
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What is a zygote?
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The fusion of 2 gametes which produces a cell with 46 chromosomes.
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When does crossing over occur?
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During meiosis in gametogenesis, when maternal and paternal DNA are joined to create a haploid gamete for the ova and sperm.
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What is crossing over?
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The breaking of a chromosome and exchange of that piece with the same from the other parental chromosome.
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What is recombination?
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the process by which progeny derive a combination of genes different from their parents', and achieved by crossing over.
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When during cell stages does crossing over occur?
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During the metaphase stage of meiosis one in gametogenesis.
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What is a centimorgan?
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A unit of measurement that lets us describe the frequency of recombination.
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What does one centimorgan infer?
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A 1% frequency of crossing over at a specific gene locus.
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What happens to linked genes when crossing over occurs?
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They become unlinked
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What is linkage?
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The proximity of two genes to each other - or a gene and a marker, like a RFLP and a disease gene.
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What increases the chance of inheriting a linked gene and RFLP together?
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Decreased distance between the two.
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How do we measure the distance between genes?
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By measuring their recombination frequency, which is represented by the centimorgan.
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So what is a genetic map?
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A map of the relative positions of genes in relation to each other, based on their recombination frequencies.
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Genetics definition:
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The field of BIOLOGY concerned with the heredity and variation of organisms
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Genomics:
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The field of GENETICS concerned with STRUCTURAL and FUNCTIONAL studies of the GENOME.
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What do Genetic Markers allow us to do?
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Observe which allele of a chromosome is inherited from a parent to a child.
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What method using genetic markers allows us to see inheritance?
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Linkage analysis
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4 types of Gene markers:
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-Genes
-RFLPs -Simple Sequence Length Polymorphisms (SSLPs) -Single Nucleotide Polymorphisms (SNPs) |
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What are Microsatellites, CA repeats, Short tandem repeats, and simple sequence repeats all examples of?
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Simple Sequence Length Polymorphisms SSLPs
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What are Nucleotide substitutions and insertions or deletions?
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Single nucleotide polymorphisms SNPs
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What are Short Tandem Repeat polymorphisms?
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Short repeats of 2,3, or 4 nt's
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Where do we find STRs in life?
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Randomly throughout vertebrate genomes
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How can different STRPs be differentiated?
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By their SIZE
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What will a person that is heterozygous for STRPs at 1 genetic locus produce?
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2 different products - which show up as 2 different markers on a gel electrophoresis.
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What migrates the farthest on a gel, heaviest (longest) sequences, or lightest/shortest?
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shortest - lightest
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How closely identical in sequence are any 2 copies of the human genome?
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99.9% Identical!!!
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What are the MAJORITY of differences between humans in the genome?
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Single base pair changes or deletions -> SNPs
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Are SNPs mono or diallelic?
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Diallelic
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How many SNPs are there between any 2 chromosomes approximately?
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2 to 3 million
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So how many SNPs are there per 1000 bp?
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1 SNP every 1000 bp
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How can SNPs be assessed?
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With high-throughput genotyping methods
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What are 2 methods for genotyping for an individual SNP?
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-Taqman assay with PCR amplification
-Primer extension assay |
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What is the basis of both Taqman assays and Primer extension assays?
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The extended primer consists of fluorescent nucleotides to allow visualization of the SNP if it is there.
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What are 3 methods for genotyping for multiple SNPs?
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-Mass spec based
-Array-based -Illumina bead array |
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What are 3 clinical uses of genotyping for SNPs?
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-Clinical diagnosis
-Prenatal diagnosis -Genetic counseling |