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Botany by James Mauseth 4th edition
chapter 16 terms
54
Biology
Undergraduate 1
11/04/2013

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Term
alleles
Definition
Versions of a gene that differ from each other in their nucleotide sequences
Term
biparental inheritance
Definition
Inheritance of genes from two parents, the most common case for nuclear genes.
Term
centimorgan
Definition
synonym for map unit
Term
complete dominance
Definition
A situation in which the presence of one allele completely masks the presence of the homologous allele.
Term
cross-fertilization
Definition
The fertilization of a gamete by a genetically distinct gamete derived from a different parent.
Term
deletion mutation
Definition
a mutation involving loss of DNA
Term
dihybrid cross
Definition
A cross in which two characters are considered simultaneously
Term
DNA polymerase
Definition
The DNA-synthesizing enzyme.
Term
dominant trait
Definition
A trait whose phenotype completely masks that of the alternative (recessive) allele in the heterozygous condition.
Term
epistasis
Definition
The control of the expression of one gene by another, distinct gene, often involving the genes for the various enzymes catalyzing a single metabolic pathway.
Term
first filial generation (F1)
Definition
The progeny of an experimental cross.
Term
gene family
Definition
A set of several copies of an ancestral gene, all located within a single haploid genome. The various copies arise through gene duplication and then may evolve independently.
Term
genotype
Definition
The set of alleles present in an organism`s genome
Term
heterozygote
Definition
A diploid organism with two different alleles for a particular gene.
Term
homozygote
Definition
A diploid organism with two identical alleles for a particular gene.
Term
incomplete dominance
Definition
A situation in which the phenotypes of both alleles of a heterozygote are expressed.
Term
independent assortment
Definition
In a double heterozygote, the distribution of one allele of one gene during meiosis is not linked to the distribution of either allele of the homologous gene.
Term
insertion mutation
Definition
A mutation involving insertion of the new DNA into a sequence of pre-existing DNA.
Term
insertion sequence
Definition
A small transposable element that contains only the genes coding for the enzymes necessary for the element's excision and insertion.
Term
inversion mutation
Definition
A mutation in which a portion of the DNA double helix is excised, turned end for end, and ligated into place with reverse order.
Term
lethal allele
Definition
An allele whose expression results in death.
Term
linkage group
Definition
A set of genes that do not undergo independent assortment, being part of one chromosome.
Term
linked genes
Definition
Genes located close to each other on a chromosome undergo crossing over only rarely, so they are attached.
Term
map unit
Definition
A measure of the separation of genes on a chromosome; one unit equals a 1% probability that crossing over will occur between them.
Term
maternal inheritance
Definition
Uniparental inheritance for genes contributed by the megagamete but not by the microgamete.
Term
monohybrid cross
Definition
A cross in which only a single trait is analyzed, disregarding all other traits.
Term
mutagen
Definition
Any chemical or physical force that causes a change in the sequence of nucleotides in DNA.
Term
mutation
Definition
Any change in the sequence of DNA.
Term
nondisjunction
Definition
During meiosis II, the nonseparation of the two chromatids of a chromosome, such that one daughter cell received both while the other daughter cell receives none.
Term
Okazaki fragment
Definition
During DNA replication, the set of short fragments that grow discontinuously along one strand of DNA and must be ligated into one continuous DNA molecule.
Term
outcrossing
Definition
Synonym for cross fertilization.
Term
parental generation
Definition
The original genes in a crossbreeding.
Term
parental type chromosome
Definition
A chromosome that, after meiosis, has not undergone crossing over
Term
phenotype
Definition
The physical, observable characteristics of an organism.
Term
pleiotropic effects
Definition
The multiple phenotypic expressions of a single allele whose activity affects various aspects of metabolism.
Term
point mutation
Definition
A mutation affecting only a single nucleotide.
Term
polyploid
Definition
Refers to a nucleus that contains three or more sets of chromosomes.
Term
primer RNA
Definition
During DNA replication, a short piece of RNA that is synthesized against open DNA and from which DNA polymerase can begin buidling a new molecule of DNA.
Term
Punnett square
Definition
The table used to easily analysis the results of a cross.
Term
pure-bred line
Definition
The homozygous dominant and homozygous recessive genotypes of a line which are selfed and used in breeding experiments.
Term
quantitative trait locus (QTL) analysis
Definition
Most phenotype characters are the result of interactions of many genes (loci); this analysis involved numerous crosses to determine just how much various genes contributed to a particular phenotype.
Term
recessive trait
Definition
A trait whose phenotype is completely masked by that of the alternative (dominant) allele in the heterozygous condition.
Term
recombinant chromosome
Definition
A chromosome that results from crossing over in meiosis, being composed of parts of the paternal and maternal homologs.
Term
replication fork
Definition
In DNA replication, the point at which the d ouble helix opens and formation of new DNA occurs.
Term
replicon
Definition
During DNA replication, a short segment of DNA that has opened and where replication is occurring.
Term
selfing
Definition
Pollinating a plant's stigma with pollen from the same plant or a plant of identical genotype.
Term
semiconservative replication
Definition
Refers to the fact that during DNA replication, one new molecule is paired with one original molecule such that in every new chromosome, half the DNA is conserved from the pre-existing chromosome.
Term
somatic mutation
Definition
A mutation in a cell that is not a gamete and does not give rise to gametes.
Term
test cross
Definition
A cross involving one parent known to be homozygous recessive for the trait being considered
Term
transposable element
Definition
A region of DNA that codes for enzymes that catalyze the release of the element and its insertion into a different site in the DNA.
Term
transposon
Definition
A large transposable element that carries, in addition to the insertion sequence, other genes that code for proteins not directly associated with transposition.
Term
triploid
Definition
A nucleus that contains three sets of chromosomes.
Term
uniparental inheritance
Definition
Inheritance of genes from just one parent, the most common case for plastid and mitochondrial genes; sperm cells typically do not contribute these organelles to the zygote.
Term
variegation
Definition
A pattern of spots, stripes, or patches in leaves or other organs, caused by plastid mutations
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