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Genetics 1
Vocab snustad first seven chapters
194
Biology
Undergraduate 1
10/19/2010

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Term
Allele
Definition
one of a pair or series of alternative forms of a gene that occur at a given locus in a chromosome; appear as dominate or recessive forms
Term
Acentric
Definition
a chromosome fragment that does not have a centromere
Term
Allopolyploids
Definition
polyploids created by hybridization between different species; contribution genomoes are qualitatively different
Term
Aneuploidy
Definition
a numerical change in the genome; individuals have an extra chromosome, are missing a chromosome, or have a combination of these anomalies
Term
Autopolyploids
Definition
polyploids created by chromosome duplication within a species ; single genome has been multiplied
Term
Barr body
Definition
the X chromosome that has been inactivated condenses into a darkly staining structure; becomes attached to the inner surface of the nuclear membrane and replicates out of step with the other chromosomes in the cell
Term
Bivalant
Definition
pair of associated homologous chromosomes that have undergone the duplication process to form a group of four chromatids
Term
Centromere
Definition
a spindle fiber attachment region of the chromosome
Term
Chiasma
Definition
visible change of partners in two of a group of four chromatids; point where one part of two chromatids is exchanged; point of crossing over
Term
Chromatid-type-chromosomal aberrations
Definition
happens after cells have replicated, during G2
Term
Chromosome painting
Definition
colorful chromosome images are created b y treating chromosome spreads with fluorescently labeled DNA fragments that have been isolated and characterized in the laboratory
Term
Chromosomal Theory of Heredity
Definition
the theory that chromosomes carry the genetic information and that their behavior during meiosis provides the physical basis of the segregation and independent assortment
Term
Chromosomal-type-chromosome aberrations
Definition
effects both chromatids; replicates with damages; occurs during G0 or G1
Term
Chromatid
Definition
one of the two identical stands resulting from self-duplication of a chromosome
Term
Chromatin
Definition
the network of thin strands formed by all the chromosomes within the nucleus
Term
Chromatin
Definition
the network of thin strands formed by all the chromosomes within the nucleus
Term
Codominate
Definition
two alleles contribute independently to the phenotype of the heterozygote; both alleles are encoding for a gene product
Term
Compound chromosome
Definition
one chromosome fuses with its homologue, or two sister chromatids become attached to each other, forming a single genetic unit; can exist stably in a cell if it only has one functional centromere
Term
Complete dominance
Definition
heterozygous is the same as homozygous; one gene is haplosufficient
Term
Concordance
Definition
frequency at which two things are the same as each other; used in twin studies
Term
Cri-du-chat syndrome
Definition
condition caused by a deletion in the short arm of chromosome 5; size of deletion varies; individuals heterozygous for the deletion and a normal chromosome have karyotype 46 del(5)(p14) and can be severely mentally and physically retarded
Term
Cytokinesis
Definition
process that physically separates the two daughter cells from each other
Term
Deletion/deficiency
Definition
a missing chromosome segment; makes part of the genome haploid in a usually diploid organism, if large enough can have a phenotypic effect
Term
Diakinesis
Definition
the pair of homologous chromosomes, still held together by the chiasmata , move to the central plane of the cell that is perpendicular to the axis of the spindle apparatus
Term
Dicentric
Definition
chromosomal fragment that has two centrosomes
Term
Dihybrid cross
Definition
test if two different traits are inherited independently and which were dominate to the others; progeny appear in a 9:3:3:1 ratio
Term
Dioecious
Definition
separate male and female individuals; plants
Term
Diploid
Definition
having two sets of chromosomes (2n); somatic cells (body cells)
Term
Diplotene
Definition
paired chromosomes of bivalents separate slightly; however they remain in close contact where they have crossed over (at the chiasmata)
Term
Dominant
Definition
a condition in which one member of an allele pair is manifested to the exclusion of the other
Term
Duplication
Definition
having an extra chromosome segment; can be attached to one of the chromosome, or it can exist as a new and separate chromosome
Term
Endomitosis
Definition
duplication of the chromosomes without division of the nucleus, resulting in increased chromosome number within a cell. Chromosome strands separate, but the cell does not divide
Term
Epistasis
Definition
when two or more genes influence a trait, an allele of one of them may have an overriding effect on the phenotype; the overriding one is epistatic to the other; genes that are suppressed are said to be hypostatic
Term
Euchromatin
Definition
genetic material that is not stained so intensely by certain dyes during interphase and that comprises many different kinds of genes
Term
Euploid
Definition
having complete chromosome sets; n, 2n, 3n,…
Term
Expressivity
Definition
extent to which a genotype is shown through by the phenotype, can be variable; not manifested uniformly
Term
Fluorescence in situ hybridization (FISH)
Definition
In situ hybridization performed using a DNA or RNA probe coupled to a fluorescent dye
Term
Gain-of-function allele
Definition
dominant mutations; a mutation that endows a gene product with a new function
Term
Gene
Definition
a hereditary determinant of a specific biological function, a segment of DNA (a unit of inheritance) located in a fixed position on a chromosome encoding one polypeptide
Term
Gene linkage
Definition
genes are inherited together on the same chromosome; can be proven when parent diatype is more prevalent then recombinant(non-parental)
Term
Genetic map
Definition
a diagram of a chromosome with distances based on recombination frequencies; measured in centiMorgans
Term
Genome
Definition
a complete set (n) of chromosome inherited as a unit from one parent
Term
Genotype
Definition
the genetic constitution of an organism
Term
Germ line
Definition
reproductive tissue of an organism; diploid cells specified to produce gametes
Term
Haploid
Definition
having one copy of each chromosome (n); in gametes/sex cells; defines a set of chromosomes called the haploid genome
Term
Hemizygote
Definition
an organism that has only one copy of a gene, common in sex (X) linked genes where father only has one X
Term
Hermaphrodite
Definition
males and female reproductive cells in the same individual
Term
Heterogametic sex
Definition
when they produce two kinds of gametes; in humans and drosophila= males (XY)
Term
Heterochromatin
Definition
chromatin that stains darkly even during interphase, often containing repetitive DNA with few genes
Term
Holandric
Definition
characteristic found only on the Y chromosome
Term
Homogametic
Definition
when they produce a single kind of gamete: in humans and drosophila= females (XX)
Term
Homologous chromosomes
Definition
chromosomes that occur in pairs, one having come from the male and the other from the female parent; contain the same array of genes; pair together during meiosis
Term
Hydromorphic
Definition
partially functional alleles; recessive alleles that are more functional
Term
Hypoploid
Definition
an organism where a chromosome, or a piece of a chromosome, is underrepresented
Term
Hyperploid
Definition
an organism where a chromosome, or a piece of a chromosome, is overrepresented
Term
Incomplete dominance
Definition
the intensity of the pigment(product of the allele) depends on the amount of a product specified by the gene; active allele is not haplosufficient
Term
Incomplete penetrance
Definition
not everyone will express the phenotype of a given genotype; exp. polydactyly
Term
Interference
Definition
the inhibition of a crossover by a nearby crossover
Term
Isoalleles
Definition
two different alleles that are functionally equivalent
Term
Inversion
Definition
a chromosome segment is detached flipped 180° and reattached to the rest of the chromosome; order of the genes is reversed on that segment
Term
Klinfelter syndrome
Definition
XXY trisomy in the sex chromosomes; phenotypically male, but show some female secondary sexual characteristics and are usually sterile; rare cases can involve more X chromosomes with one Y chromosome
Term
Leptotene
Definition
the duplicated chromosomes condense out of the diffuse chromatin network
Term
Locus
Definition
a fixed position on a chromosome that is occupied by a given gene or one of its allele
Term
Loss-of-function allele
Definition
alleles that have little or no discernible effect in heterozygous condition with a wild-type allele; usually recessive mutations
Term
Metaphase I
Definition
paired chromosomes orient toward opposite poles of the spindle; ensures that when the cell divides one member of each pair will go to each pole
Term
Meiosis
Definition
process that reduces the diploid state to the haploid state-reduces the number of chromosomes; resulting haploid cells either directly become gametes or divide to produce cells that later become gametes
Term
Meiosis II
Definition
acts similarly to mitosis except now each daughter cell contains one haploid set of chromosomes
Term
Microtubules
Definition
components of the cytoskeleton that execute the distribution of duplicated chromosomes to the daughter cells TUBULIN
Term
Mitosis
Definition
process of the cell cycle that distributes the duplicated chromosomes equally and exactly to the daughter cells
Term
Monoecious
Definition
separate male and female flowers on the same individual
Term
Monohybrid cross
Definition
cross where a single trait is being studied; progeny consistently appear in a 3:1 ratio
Term
Mosaic
Definition
genetically different among somatic cells
Term
Monosomy
Definition
one chromosome is missing in an otherwise diploid individual
Term
Multiple allelism
Definition
more then two recognizable alleles of a gene (rabbit coat color)
Term
Mutant
Definition
altered form of the wild-type allele that must have arisen during evolution
Term
Nondisjunction
Definition
failure of the chromosomes to disjoin during of the meiotic divisions; could result from faulty chromosome movement, incomplete pairing, or centromere malfunction; results in too many chromosome in some daughter cells and too few in others. Examples: in meiosis, both members of a pair of chromosome go to one pole so that the other pole does not receive either of them; in mitosis, both sister chromatids go to the same pole
Term
Norm of Reaction
Definition
set of relationships between heredity and environment; single genotype can produce different phenotypes under different environmental conditions; opposite is also true
Term
Pachytene
Definition
homologous chromosomes are fully paired; each pair consist of two duplicated homologues, which themselves consist of two sister chromatids ; time when crossing over occurs
Term
Paracentric
Definition
inversion where the inverted segment does not include the centromere; leads to a dicenric (two centromeres) and acentric (no centromeres) chromosome; more lethal
Term
Penetrance
Definition
proportion of individual of a given genotype to show the coordinating phenotype
Term
Pericentric
Definition
inversion where the inverted segment includes the centromere; results in eache having one centromere
Term
Phenocopy
Definition
environmentally caused phenotype that resembles a different genotype
Term
Phenocomelia
Definition
rare dominate trait, severely underdeveloped appendages; thalidomide (a teratogen) caused same phonotypical effect without any genetic coding ; exp of phenocopy
Term
Phenylketonuria
Definition
recessive disorder of amino acid metabolism; genetic disorder that can be moderated by the exposure to low-phenylalanine diets; Example of diet as an environmental effect on expression
Term
Pleiotropic
Definition
single gene has more than one unrelated genetic effect
Term
Polydactyly
Definition
example of incomplete penetrance; dominant mutation that is manifested in only some of its carriers; have the genotype, but not the phenotype
Term
Polyploidy
Definition
the presence of extra chromosome sets; common in plants but very rare in animals because it interferes with the sex-determination mechanism; usually steril
Term
Pseudoautosomal genes
Definition
genes that are present on both the X and Y chromosomes near the ends of the short arms; follow the patterns of inheritance of an autosomal gene; in males, these regions are what mediate pairing between the X and Y chromosome
Term
Recessive
Definition
a term applied to one member of an allelic pair lacking the ability to manifest itself when the other is present
Term
Reciprocal translocation
Definition
when pieces of two nonhomologous chromosome s are interchanged without any net loss of genetic material
Term
Recombination
Definition
the separation of linked genes and the formation of new gene combinations
Term
Robertsonian translocation
Definition
nonhomologous chromosomes fuse at their centromeres; if two acrocentric chromosomes fuse they produce a metacentric chromosome, the tiny short arms of the participating chromosomes are lost in the process; evolution- chromosome 2 in humans was formed from the combining of two acrocentric chromosomes in chimps
Term
Rule of Dominance
Definition
if heterozygote expresses the characteristic of one parent and not the other, it is considered dominant
Term
Rule of Segregation
Definition
when a hybrid makes gametes, the two alleles separate clearly
Term
Sex-determining region Y (SRY)
Definition
gene located just outside the pseudoautosomal region; Y-linked gene in humans encoding a protein, the testis-determining factor, which plays a key role in male development
Term
Synapsis
Definition
process of pairing between homologues; usually accompanied by the formation of the synaptonemal complex
Term
Synaptonemal complex
Definition
proteinaceous structure between pairing chromosomes; consists of three parallel rods, one associated with each of the chromosomes, one located mid-way between them ; occurs during zygotene
Term
Testcross
Definition
backcross to the recessive parental type, or a cross between genetically unknown individuals with a fully recessive tester to determine whether an individual is question is heterozygous or homozygous for a certain allele
Term
Testicular feminization syndrome (TFS)
Definition
XY female; lacks receptor for TDF even if it is being produced by SRY
Term
Testis-determining factor(TDF
Definition
product of the SRY gene; a protein produced early in development of male mammals that stimulates the differentiation of the testes from the embryonic gonads
Term
Tetrad
Definition
quadruple group of chromatids that is formed by the association of duplicated homologous chromosomes during meiosis
Term
Tetrasomic
Definition
2n+2; 4 copies of one chromosomes and 2 of all the others
Term
Transcription
Definition
process where RNA is formed along a DNA template
Term
Translation
Definition
protein synthesis directed by specific messenger RNA
Term
Translocation
Definition
a segment from one chromosome is detached and reattached to a different chromosome
Term
Trisomy
Definition
triplication of a certain chromosome
Term
Trivalent
Definition
an association between three chromosomes during meiosis
Term
Turner syndrome
Definition
females with a single X chromosome and a diploid complement of autosomes; fundamentally female in phenotype but sterile
Term
Univalent
Definition
an unpaired chromosome at meiosis
Term
X-chromosome
Definition
a chromosome associated with sex determination. In humans the female has two and male has one; large submetacentric
Term
Y-chromosome
Definition
the male chromosome which will pair with the X-chromosome during meiosis; in humans it is responsible for the male characteristics and in drosophila it is needed for sterility; small acrocentric
Term
Zygotene
Definition
homologous chromosomes pair together; where synapsis occurs
Term
karyokinesis
Definition
division of nucleus
Term
Mendel 1865
Definition
disc. peas inheritance
Term
Sutton-Boveri 1903
Definition
disc. genes on chromosomes
Term
p=(n!/s!t!)p^s*q^t
Definition
probability of two events happening equation
Term
cohesin
Definition
protein complex that sticks chromotids together at centromere
Term
Metacentric, submetacentric, acrocentric
Definition
3 placements of centromere
Term
heterochromatin
Definition
dark stained, no trascription/translation but functions in mitosis/meiosis
Term
euchromatin
Definition
light stained, genetically active
Term
kinetichore
Definition
part of centromere where spindle fibers attach
Term
facts about telomeres
Definition
repeated DNA, not sticky, universal in vertabrates, controlls amount of cell division
Term
telomerase
Definition
makes telomeres for contantly dividing cells, uh oh, like tumor cells
Term
region of chromosome after secondary constriction
Definition
satellites are separated from chromosome by this structure
Term
nuclear organizer
Definition
located on 2ndary constriction, has ribosomal RNA genes that make ribosomes
Term
chromosome complement
Definition
characteristic set of chromosomes of a species
Term
supernumerary chromosome
Definition
distinctive additional chromosome, not a copy, that may or may not be active
Term
Cyclin dependent kinase
Definition
regulates cell cycle at two checkpoints (after G1 and G2)
Term
G-0
Definition
cell out of cell cycle. mature tissue or non dividing blood cell for example
Term
maturation promoting factor
Definition
cycling and cyclin dependent kinase, regulatory molecule levels go up and down do to phosphorylation and dephosphorylation
Term
kinase
Definition
breaks down nuclear envelope by phosphorylating lamins within envelope
Term
apoptosis
Definition
programmed cell death
Term
terminalization
Definition
chiasmus move toward ends
Term
diakinesis
Definition
when terminalization occurs
Term
life cycle length,
cheapness,
known genetic makeup / prev. studied
types of reproduction
Definition
reasons for model organisms
Term
no environmental modification, one gene per trait, complete penetrance (geno=pheno)
Definition
3 things pedigrees assume
Term
spermatagonium - primary spermatocyte - secondary spermatocyte - differentiating spermatid - sperm + residual bodies
Definition
steps of spermatogenesis
Term
seminiferous tubules of testes
Definition
location of spermatogenesis
Term
oogonium - primary oocyte - secondary oocyte + polar body - ovum + 3 polar bodies
Definition
steps of oogenesis
Term
gametogenesis
Definition
formation of gametes
Term
dictyotene
Definition
suspended state of diplotene for oocytes
Term
Mom
Definition
mitrochondrial DNA from which parent?
Term
polymorphic
Definition
more than one allele prevalent in population
Term
alcohol dehydrogenase
Definition
ummm idk
Term
multiple allelism
Definition
common; more than two recognizable alleles for a gene,
Term
polygenic
Definition
multiple gene pairs for the same phenotype
Term
isoalleles
Definition
2 different alleles that are functionally equivalent but distinguishable. eg (IA1>IA2>IA3=IB)
Term
phenocopy
Definition
environmentally caused phenotype resembling a different phenotype
Term
# of x chromosomes/ number of each autosome
Definition
What sex am I? Greater than or equal to 1 = female, less than or equal to .5 = male
Term
Kleinfelter sydrome (male human)
Definition
XXY
Term
Turner syndrome (female)
Definition
X0
Term
Swyer Syndrome (female)
Definition
XY abnormal
Term
de la Chapelle syndrome (male)
Definition
XX abnormal
Term
Lyon Hypothesis
Definition
barr body = inactivated x
Term
mosaic
Definition
differences between somatic cells, eg. different X inactivation in each cell
Term
X inactive specific transcript gene
Definition
during development, makes transcript to attach to one Xq to shut it down; random which X; common to mammals; in kangaroos, paternal X is always inactivated!
Term
clastogen
Definition
agent that causes break in chromosomes
Term
interstitial deletion (versus terminal deletion)
Definition
deletion in middle of chromosome (versus the end)
Term
deletion
Definition
normal chromosome loops in pairing
Term
duplication
Definition
during pairing, chromosome with extra segment looped
Term
pericentric (middle of loop) but paracentric is bad news bears
Definition
types of inversions (which is more of a big deal)
Term
robertsonian translocation
Definition
acrocentric chromosomes >> sub metacentric chromosome
Term
position effect
Definition
genes expressed differently depending on where in the genome
Term
oncogene
Definition
gene that drives cell to cancer
Term
Philadelphia chromosome
Definition
first chromosomal abnormality linked to cancer (leukemia)
Term
monoploid
Definition
haploid when shouldnt be
Term
chromosomal duplication w/out division; diploid gamete fertilization; double fertilization
Definition
three possibilities for polyploidy
Term
colchicine
Definition
inhibits tubulin - and chromosome separation
Term
trisomy
Definition
2n + extra chromosome
Term
monosomy
Definition
2n - missing chromosome
Term
tetrasomy
Definition
2n + two extra of same chromosome
Term
nullisomy
Definition
2n - pair of chromosomes
Term
nondisjunction
Definition
failure of chromosomes to separate
Term
amphidiploid
Definition
polyploid acting like a diploid
Term
trisomy 21
Definition
down syndrome
Term
Morgan
Definition
disc. gene pairs inherited together, separation of genes via crossing over
Term
linkage
Definition
tendency of genes on the same chromosome to be inherited together
Term
Recombinance frequency
Definition
recombinants / (parentals + recombinants)
Term
linked if RF is less than .5 (P>R)
Definition
linkage in relation to recombinance frequency
Term
Creighton and McClintock
Definition
disc. (saw) crossing over
Term
1 centimorgan
Definition
1% recombination = ?
Term
syntenic
Definition
gene loci on the same chromosome are by definition _______
Term
psuedosutosomal genes
Definition
genes on both x and y chromosomes mimickick autosomal inheritance
Term
Giemsa (light G/C rich)
Definition
g banding
Term
light A/T rich
Definition
R - banding
Term
quinacrine
Definition
q - banding
Term
stain around the centromere
Definition
c - banding
Term
polytene
Definition
giant chromosomes produced by interphase replacation without division and consisting of many identical chromatids arranged side by side in a cable like pattern
Term
chromocenter
Definition
a collection of the centrosomes of the polytene chromosomes
Term
mitogen
Definition
stimulates mitosis for chromosome preparations
Term
chromosome 11, p arm, region 1, band 3
Definition
chromosome naming: where is 11p13?
Term
p arm
Definition
short arm of chomosome
Term
q
Definition
long arm of chromosome
Term
probability= (n!/s!t!)p^s*q^t
Definition
probability formula
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