| Terms |
Definitions |
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XO
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grasshoppers
crickets
roaches
insects
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duplication
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repeats a segment
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map units
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one= 1% recombination frequency
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Chiasma
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a cross-shaped structure commonly observed between nonsister chromatids in meiosis;the site of crossing over
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inversion
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chromosomal fragment is reattached to the original chromosome
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Duchenne muscular dystrophy
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sex linked disease (males)
progressive weakening of the muscles and loss of coordination
afflicted rarely live past 20's
result of an absence of a key muscle protein (dystrophin)
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Recombinant
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An offspring whose phenotype differs from that of the parents. Also refers to the phenotype itself.
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Meiocytes
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cell in which meiosis takes place
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Cytoplasmic segregation
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segregation in which genetically different daughter cells arise from a progenitor that is a cytohet
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cytogenetic maps
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locate genes with respect to chromosomal features
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recombinant types
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offspring with new combinations of traits
don't exactly look like parents
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Down Syndrome
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A condition of retardation and associated physical disorders caused by an extra chromosome in one's genetic makeup
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crossing over
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The reciprocal exchange of genetic material between nonsister chromatids during prophase 1 of meiosis
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Nondisjunction
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the failure of homologs (at meiosis) or sister chromatids (at mitosis) to separate properly to opposite poles
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Deletion
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A deficiency in a chromosome resulting from the loss of a fragment through breakage.
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Nondisjunction
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the failure of homologs (at meiosis) or sister chromatids (at mitosis) to separate properly to opposite poles
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Gametes
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a specialized haploid cell that fuses with a gamete of the opposite sex or mating type to form a diploid zygote
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linkage map
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a genetic map based on recombination frequencies
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monosomy
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zygote has only one copy of a particular chromosome
2n-1
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Hemophilia
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A human genetic disease caused by a sex linked recessive allele resulting in the absence of one or more blood clotting proteins; characterized by excessive bleeding following injury.
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Wild Type
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An individual with the normal (most common) phenotype.
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Translocation
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A mutation where a segment is moved from one chromosome to a nonhomologous chromosome
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Daughter cells
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two identical cells formed by the asexual division of a cell
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Trisomic
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Referring to a diploid cell that has three copies of a particular chromosome instead of the normal two.
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Dyads
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a pair of sister chromatids joined at the centromere, as in the first division of meiosis
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chromosome theory of inheritance
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the behavior of chromosomes during meiosis and fertilization accounts for inheritance patterns
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Genomic Imprinting
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A phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parent.
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Cytogenetic Map
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A chart of a chromosome that locates genes with respect to chromosomal features distinguishable in a microscope.
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Chromosome theory of heredity
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a unifying theory stating that inheritance patterns may be generally explained by assuming that genes are located in specific sites on chromosomes
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Histones
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a type of basic protein that forms the unit around which DNA is coiled in the nucleosomes of eukaryotic chromosomes
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Scaffold attachment region (SAR)
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positions along DNA at which the DNA is anchored to the central scaffold of the chromosome
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