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56 Cards in this Set
- Front
- Back
proband
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person from the pedigree is initiated
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consanguinity
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mating between closely related people
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concordance
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percentage of twin pairs that are concordant (both have the trait)
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amniocentesis
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procedure for obtaining a sample of amniotic fluid; analyzed for chemical, DNA, and chromosomal
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Unlinked genes
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1:1:1:1 ratio
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Partial linkage
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PAR > REC
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Complete Linkage
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PAR: 1 REC: 0
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Recombinant distance
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(# Recombinant progeny / #Total progeny) X 100
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Chance of a double cross over
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SCO1 X SCO2 = DCO
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crossover interference
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number of observed double crossovers is usually less than expected
(1-Coefficient of Coincidence) Ex 0.6 means 60% did not occur as predicted |
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Coefficient of Coincidence
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observed DCO/ expected DCO
-expected: probability of crossover (single recombination frequences, or map distance) X total progeny |
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Cell fusion
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mapping technique; analysis of human tissue in culture
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LOD analysis
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mapping technique; based on pedigree
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LOD values
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STUDY power point
LOD: logarithm of odds (probability that genes are actually linked) LOD > 3.0: linkage. LOD < -2.0: no linkage (exclusion). LOD between 3.0 & -2.0: inconclusive |
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pericentric inversion
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chromosome inversion that includes the centromere in the inverted region
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alternate segregation
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type of segregation that takes place in heterozygote for a translocation
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allopolyploid
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condition in which the sets of chromosomes of a polyploid individual possessing more than two haploid sets are derived from two or more species
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autopolyploid
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sets of chromosomes of a polyploid individual possessing more than two haploid sets are derived from an identical species member
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AC element
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transposable element in Maize; autonomous due to a gene that it contains which encodes a transposase enzyme
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nonrecombinant gametes
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parental gametes; gametes that contain only original combinants of alleles present in the parents
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coupling
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cis configuration; wild-type alleles are found on one chromosome and mutant alleles are found on other
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repulsion
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trans configuration: each chromosome contains one wild type and one mutant alleles
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genetic maps
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chromosome maps calculated by using the genetic phenomenon of recombination
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somatic-cell hybridization
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requires the fusion of different types of cells; cells altered by viruses or tumors will divided indefinitely
provide cell line |
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heterokaryon
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cell with two nuclei
*hybrid cells shed chromosomes as they divide (lost from only one species-lost of human chromosomes in human/mice tumor cross) |
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episomes
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plasmids that are capable of freely replicating and able to integrate into the bacterial chromosomes
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intragenic mapping
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different sites within a single gene are mapped using techniques similar to those described for mapping bacterial genes by transduction
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High Frequency Recombination (Hfr) Strains
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-The F-factor integrates into the bacterial chromosome.
-F integration occurs at many different sites in the bacterial chromosome. |
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electroporation
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used prior to transformation; creates "pores" in bacteria, allowing DNA fragments to pass through
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Mapping Phage Chromosomes
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-Recombination produces parental and recombinant phage
-Recombinant frequency is used to map phage genes. |
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Map distance (phage)
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= [#recombinant plaques / # total] X100
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Fine Structure Mapping
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Mapping distances within a gene.
-each alleles: DNA sequence change |
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cistron
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-segment of DNA that contains all the information for production of single polypeptide
-mutant alleles within one cistron will not complement |
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complementation
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production of normal phenotype in an individual heterozygous for two closely related mutations with one on each homologous chromosome and at a slightly different position
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Retrovirus
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-virus w/ RNA genome
-reverse transcriptase gag: viral capsid proteins pol: integrase and reverse transcriptase env: viral envelope proteins may also contain oncogenes (stimulate cell divisions, cause tumors) |
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HIV
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-infects T cell
-cripples immune system -leads to AIDS |
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RII locus and fine structure mapping
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RII mutants: produce r (rough) plaques on E. coli strain B but not K
Wild type: smooth plaques on E. coli strains B and K by crossing more than one mutant type, one can tell if the mutations are on the same cistron (if not, complementation will result and the phage will revert to wild type) |
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Chromosome rearrangements affect chromosome pairing in ____
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meiosis I
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Haplo-insufficient
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lower gene dosage; abnormal development
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triplo-abnormal
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too high gene dosage; abnormal development
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heterokaryon
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used in cell fusion mapping
-Human chromosomes are lost from hybrid cells, giving lines containing different human chromosomes |
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paracentric inversion
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have inversion loops in Meiosis I (no centromere)
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Nucleotide
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The linked repeating unit of DNA that is made up of a sugar, phosphate, and a base.
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Retrotransposon
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(also called Class II transposons) Elements that transpose through an RNA intermediate.
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Fine structure map
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A technique for mapping DNA that uses the probability of the rarest instances of recombination to determine the order of genes and the distance between them.
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Coefficient of Coincidence
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The ratio of observed double crossovers to expected double crossovers.
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Nucleosome
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A core particle of DNA wrapped around an octamer of eight histone proteins two times. The simplest level of chromatin structure.
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Translocations
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exchanges between non-homologous chromosomes
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Robertsonian translocations
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exchanges of whole chromosome arms
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Aneuploidy
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2n +/- x chromosomes
types end in -omy cause: Non-disjunction during the first or second meiotic division. |
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Downs, Edwards
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Trisomy 21, 18
Down: mental retardation Edwards: death prior to age one |
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purines
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guanine and adenine
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pyrimidines
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cytosine, thymine, uracil
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attachment on DNA carbon ends
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phosphate: 5'
base: 1' |
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Chargaff’s rule
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A/T and C/G ratios
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cytosine methylation
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key role in imprinting and gene activation (methylation inactivates)
-methyl (CH3) group added to pyrimidine cytosine (or adenine in bacteria) |