Polyploidy

polyploidy

Having more than one pair of homologous chromosomes

polyploidization

the formation of polyploid species by whole genome duplication

allopolyploid

polyploid formed through hybridization between two species

autopolyploid

polyploid formed through genome duplication within a species

diploid

containing two complete sets of chromosomes (one from each parent)

triploid

containing three complete sets of chromosomes (one from one parent and two from the other)

tetraploid

containing four complete sets of chromosomes (two from each parent)

homologous chromosomes

chromosomes that share the same genes at the same loci positions

meiosis

cell division that results in gametes (eggs, sperm, spores)

homozygous

having two identical alleles of a gene

heterozygous

having two different alleles of a gene

hybrid vigor

a hybrid offspring having higher growth rates, mass, or fertility than its parents

flow cytometry quantifies…

relative genome size

flow cytometry does NOT quantify…

chromosome number or ploidy level

c-value

genome size; the amont of DNA in a haploid nucleus; measured in picograms (pg) or base pairs (bp)

G1 phase

phase of cell growth with two copies of each chromosome

G2 phase

phase of cell growth with four copies of each chromosome

coefficient of variation (CV)

measure of accuracy of peaks; ideally between 1% and 5%; standard deviation divided by mean, multiplied by 100

internal standard

plant tissue with known genome size that is co-chopped with target species in order to determine relative genome size of target

negative control

internal standard nuclei isolated without dye; must be included with each run to make sure protocol and machine are working

positive control

internal standard nuclei isolated with dye; must be included with each run to make sure protocol and machine are working

nuclei isolation buffer (NIB)

Solution that stabilizes plant nuclei and permits dye to bind to DNA; many recipes but all are made up of the same fundamental building blocks.

organic buffer substances

retains pH of solution, ensures compatibility with dye, and keeps nuclei intact. Otto example: Na2HPO4× 12 H20

non-ionic detergents

releases and cleans nuclei, minimizes debris. Otto example: tween-20

chromatin stabilizers

stabilizes chromatin and removes histones. Otto example: Na2HPO4× 12 H20

chelating agents

prevents DNA degradation (blocks DNAse activity by binding to divalent cations, which are nuclease cofactors). Otto example: citric acid

inorganic salts

keeps ionic balance. Otto example: Na2HPO4× 12 H20

reductants

prevent oxidation. Otto example: B-mercaptoethanol

fluorochrome

fluorescent dyes used in flow cytometry