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16 November, 2015 - 15:22
alternation of generations a life-cycle type in which the diploid and haploid stages alternate
aneuploid an individual with an error in chromosome number; includes deletions and duplications of chromosome segments
autosome any of the non-sex chromosomes
chiasmata (singular = chiasma) the structure that forms at the crossover points after genetic material is exchanged
chromosome inversion the detachment, 180° rotation, and reinsertion of a chromosome arm
crossing over (also, recombination) the exchange of genetic material between homologous chromosomes resulting in chromosomes that incorporate genes from both parents of the organism forming reproductive cells
diploid-dominant a life-cycle type in which the multicellular diploid stage is prevalent
euploid an individual with the appropriate number of chromosomes for their species
fertilization the union of two haploid cells typically from two individual organisms
gametophyte a multicellular haploid life-cycle stage that produces gametes
germ cell a specialized cell that produces gametes, such as eggs or sperm
haploid-dominant a life-cycle type in which the multicellular haploid stage is prevalent
interkinesis a period of rest that may occur between meiosis I and meiosis II; there is no replication of DNA during interkinesis
karyogram the photographic image of a karyotype
karyotype the number and appearance of an individuals chromosomes, including the size, banding patterns, and centromere position
life cycle the sequence of events in the development of an organism and the production of cells that produce offspring
meiosis II the second round of meiotic cell division following meiosis I; sister chromatids are separated from each other, and the result is four unique haploid cells
meiosis I the first round of meiotic cell division; referred to as reduction division because the resulting cells are haploid
meiosis a nuclear division process that results in four haploid cells
monosomy an otherwise diploid genotype in which one chromosome is missing
nondisjunction the failure of synapsed homologs to completely separate and migrate to separate poles during the first cell division of meiosis
polyploid an individual with an incorrect number of chromosome sets
recombinant describing something composed of genetic material from two sources, such as a chromosome with both maternal and paternal segments of DNA
reduction division a nuclear division that produces daughter nuclei each having one-half as many chromosome sets as the parental nucleus; meiosis I is a reduction division
somatic cell all the cells of a multicellular organism except the gamete-forming cells
sporophyte a multicellular diploid life-cycle stage that produces spores
synapsis the formation of a close association between homologous chromosomes during prophase
tetrad two duplicated homologous chromosomes (four chromatids) bound together by chiasmata during prophase I
translocation the process by which one segment of a chromosome dissociates and reattaches to a different, nonhomologous chromosome
trisomy an otherwise diploid genotype in which one entire chromosome is duplicated
Xinactivation the condensation of X chromosomes into Barr bodies during embryonic development in females to compensate for the double genetic dose