Exam 1 Flashcards
(163 cards)
1
Q
age of genetic science
A
150-160 years old
2
Q
GMO examples
A
1994 Flavr Savr, 2009 goats, 2015 chickens
3
Q
applications of genetics
A
cloning, forensic science, food, biotechnology, human genetics
4
Q
divisions of genetics
A
transmission, molecular, population
5
Q
transmission genetics
A
how genetic information is passed from one generation to the next
6
Q
molecular genetics
A
structure and function of DNA molecules
7
Q
population genetics
A
how genetic differences change in populations over time
8
Q
model organisms
A
how we experiment genetically
9
Q
E. coli model organism
A
prokaryote, short generation time, protein expression, gene regulation studies
10
Q
S. cerevisiae model organism
A
eukaryote, short generation time, easy manipulation, basic cell biology
11
Q
C. elegans model organism
A
well-mapped genetic structure (959 cells), 3-4 day generation, transparent, development, aging
12
Q
D. melanogaster model organism
A
fly, easy and cheap to culture, 10 day life cycle, many embryos, external development, genetic tools
13
Q
A. thaliana model organism
A
mustard plant, The Model Plant, genetics, development, plant-microbe interactions
14
Q
D. rerio
A
zebra fish, share 70% of genes with humans, 90 day generation, transparent embryos, external development, drugs and toxicology studies, tissue regeneration
15
Q
M. musculus
A
mouse, shares 85% of genes with humans, 50 day generation time, widely used disease models, drug therapies
16
Q
Does the estimated number of genes in an organisms reflect evolutionary complexity?
A
No, evolutionary complexity is determined by the layers of regulation of gene expression.
17
Q
characteristics of model organisms
A
short generation time, manageable numbers of progeny, adaptability to the lab, inexpensive to rear
18
Q
what is a chromosome
A
DNA storage container
19
Q
nucleosome
A
DNA wrapped around a histone core
20
Q
chromatosome
A
nucleosome + histone protein (H1 linker)
21
Q
chromatin
A
DNA wrapped around histones (DNA + protein)
22
Q
haploid
A
1 copy in every cell
23
Q
diploid
A
two copies in every cell
24
Q
karyotype
A
the picture of all chromosomes in an individual
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telomere
tips of the chromosomes
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centromere
center of chromosome where two sister chromatids are attached
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kinetochore
a protein structure that attaches chromosomes to spindle microtubules during cell division
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(on karyotype) metacentric
centromere in the middle
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(on karyotype) submetacentric
centromere slightly away from the middle
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(on karyotype) acrocentric
centromere very far away from the middle
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(on karyotype) telocentric
sister chromatids attached at the telomeres
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chromosome territories
you can map out chromosome territories in the cell because they are so condensed.
33
function of mitosis
preserve chromosome number and make two identical daughter cells.
34
5 stages of mitosis
interphase, prophase, metaphase, anaphase, telophase
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mitosis interphase
DNA is replicated
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mitosis prophase
chromosomes start to condense and mitotic spindle forms
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mitosis metaphase
chromosomes line up in the middle of the cell
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mitosis anaphase
sister chromatids separate and move to opposite sides of the cell
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mitosis telophase
end of the process, nuclear membrane reforms around each daughter nucleus
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mitosis prometaphase
nuclear envelope disintegrates, spindle microtubules anchor to kinetochores
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cytokinesis
cytoplasm divides
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mitosis G0 phase
stable, nondividing period
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mitosis G1 phase
growth and development of the cell, G1/S checkpoint
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mitosis S phase
duplication of DNA
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mitosis G2 phase
preparation for division, G2/M checkpoint
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function of meiosis
two divisions, reduces chromosome number to half (2n:n:n)
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meiosis stages
interphase, meiosis 1 (mitosis stages), interkinesis, meiosis 2 (mitosis stages), cytokinesis
48
synaptonemal complex (SC)
a protein structure that forms between homologous chromosomes (two pairs of sister chromatids) during meiosis and is thought to mediate synapsis and recombination during meiosis I in eukaryotes.
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meiosis prophase 1
crossing over, nuclear membrane breaks down
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meiosis metaphase 1
homologous pairs of chromosomes line up in center
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meiosis anaphase 1
homologous chromosomes separate and are pulled to separate sides of the cell
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meiosis telophase 1
chromosomes arrive at spindle poles and cytoplasm divides
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meiosis prophase 2
chromosomes recondense
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meiosis metaphase 2
individual chromosomes line up in the middle
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meiosis anaphase 2
sister chromatids separate and are pulled to separate sides of the cell
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meiosis telophase 2
chromosomes arrive at spindle poles and cytoplasm divides
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spindle microtubules
they lengthen and shorten at the centrosome, essential for chromatin separation (43-44 of W1L2)
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bivalent
a pair of homologous chromosomes that are physically connected and form a tetrad during meiosis
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tetrad
a structure formed during meiosis where two homologous chromosomes, each consisting of two sister chromatids, are paired together, creating a group of four chromatids called a tetrad
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disjunction
homologous chromosomes move apart toward the opposite poles of the cell in anaphase I
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nondisjunction
a situation where chromosomes fail to separate properly during cell division (meiosis), resulting in daughter cells with an abnormal number of chromosomes
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chiasma
a physical link between two homologous chromosomes during meiosis. Chiasmata are formed at sites where DNA breaks are recombined, creating crossovers
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cohesin
a protein complex that holds sister chromatids together during cell division
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separase
Separase is a protein enzyme that plays a crucial role in chromosome segregation during cell division by cleaving the protein complex "cohesin"
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shugoshin
Shugoshin is a protein that protects cohesin at centromeres, which is important for chromosomal stability during cell division
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pangenesis concept
genetic info from around the body travels to the reproductive organs where it is transferred to the gametes.
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preformationism
there is a fully-formed tiny person inside the gamete
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Germ-Plasm theory
germ line tissue in the reproductive organs contains a complete set of genetic information that is transferred directly to the gametes
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blending inheritance
sex cells contain the essence of the parents, the union of these cells blends the essence (red + white = pink)
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Gregor Mendel
father of modern genetics
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gene
determines a trait
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alleles
alternate forms of a gene (gametes have 1, adult cells have 2)
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locus
a specific place on a chromosome occupied by an allele
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homozygous
two alleles are the same
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heterozygous
two alleles are different
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monohybrid cross
a cross involving a single trait
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dihybrid cross
a cross involving two traits
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Mendel's conclusions
heredity is not blending, 2 determinants/trait, in a heterozygote 1 may be dominant 1 may be recessive
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Mendel's 1st law: Law of Segregation
During gamete formation, alleles separate or segregate from each
other. Half of the gametes carry one member of the pair and the other half carry the other member of the pair.
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genotype
genetic constitution of an organism
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genotypic ratio
ratio of genotypes from a cross
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phenotype
appearance of an organism
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phenotypic ratio
ratio of phenotypes from a cross
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backcross
crossing F1 back to either parental type
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reciprocal cross
reverse male and female phenotypes
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test cross
one parent is homozygous recessive - to determine genotype of other parent
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Mendelian disorders in humans
Tay-Sachs disease, Sickle Cell Anemia, Thalesemia
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Mendel's 2nd Law: Law of Independent Assortment
Different genes assort independently in gamete formation.
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Multiplication Rule
if two events are independent, the probability that they will occur together is the product of their separate probabilities. P(a and b)=P(a)xP(b)
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Additive Rule
if two events are independent, the probability that at least one will occur is the sum of their separate probabilities. P(a or b)=P(a)+P(b)
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hypotheses
a statement about the proposed inheritance of a trait. For example, “inheritance of flower color in snapdragons is controlled by a single gene with two alleles showing incomplete dominance.”
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null hypothesis
the observed values = the expected values and differences are due to random chance.
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degrees of freedom
phenotypic categories -1
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chi-squared statistic
sum of (obs-exp)2/exp
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interpreting chi-squared statistic
if your chi-squared statistic is less than the critical value, it is due to random chance. null accepted.
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pleiotropy
one gene affects more than 1 trait
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dominance
phenotype of the heterozygote is same as phenotype of one of the homozygotes
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incomplete dominance
phenotype of the heterozygote is intermediate to the phenotypes of the two homozygotes
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codominance
phenotype of the heterozygote includes phenotypes of both homozygotes
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incomplete penetrance
when less than 100% of a given genotype shows the phenotype it is supposed to
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variable expressivity
the gene shows variation in the level of expression of the phenotype, but all who have the genotype show the phenotype to some level. ex: marfan syndrome
102
viability variations
some genetic variations lead to changes in life expectancy or fetal death
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universal donor
type o
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universal receiver
type ab
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gene interactions
when multiple genes influence a single trait
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wild type
phenotype (or gene) found in nature
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mutant or variant
contains a mutation
108
nomenclature: mutation is recessive
abbreviation is not capitalized
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nomenclature: if mutation is dominant
gene abbreviation is capitalized
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epistasis
when a gene at one location affects the expression of a gene at another location
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dominant epistasis (squash color example)
dominant allele of one gene masks expression of another gene. 12:3:1 ratio
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recessive epistasis (horse coat color example)
recessive allele of one gene masks expression of another gene. 9:4:3 ratio
113
duplicate recessive epistasis (snail example)
9:7 ratio
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duplicate dominant epistasis (seed capsule example)
15:1 ratio
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duplicate interaction (pig coat example)
two separate gene pairs both
influence the same trait. 9:6:1 ratio
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dominant and recessive epistasis
13:3
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autosomes
pair of chromosomes common to both sexes
118
sex chromosomes
pair of chromosomes different between each sex
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males are called the what in reference to their sex
heterogametic sex
120
women are called the what in reference to their sex
homogametic sex
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primary pseudoautosomal region
top tip of sex chromosomes
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secondary pseudoautosomal region
bottom tip of sex chromosomes
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where are x and y chromosomes homologous
pseudoautosomal regions
124
insects with haploidy
male bees are n female bees are 2n
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haplodiploidy
sex is determined by number of chromosomes
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environmental sex determination
can change via temp, location (limpets), etc
127
sexual phenotype in drosophila: XX
female
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sexual phenotype in drosophila: XY
male
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sexual phenotype in drosophila: XO
male
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sexual phenotype in drosophila: XXY
female
131
sexual phenotype in drosophila: XXX
metafemale
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sexual phenotype in drosophila: XXXY
metafemale
133
sexual phenotype in drosophila: XX with three haploid sets of autosomes
intersex
134
sexual phenotype in drosophila: XO with three haploid sets of autosomes
metamale
135
sexual phenotype in drosophila: XXXX
metafemale
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in humans: XO
Turner's Syndrome
137
Turner's Syndrome
Underdeveloped sex organs, sterile, short, web of skin from neck to shoulder, heart abnormalities, hearing impairment, IQ can be near normal but often reduced, frequency = 1/2500 live female births
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in humans: XXY
Klinefelter's Syndrome
139
Klinefelter's Syndrome
Underdeveloped sex organs, sterile, tall and lanky, some breast development mild IQ reduction, frequency = 1/1000 male births
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in humans: XYY
Jacob's Syndrome
141
Jacob's Syndrome
tall, acne, behavioral problems, mild developmental delay
142
sex chromosome aneuploidy
where an individual has an abnormal number of sex chromosomes (X and Y)
143
what causes sex chromosome aneuploidy?
nondisjunction of sex chromosomes
144
Morgan's experiments
eye color in flies is sex-linked
145
Bridge's experiments
revealed nondisjunction of sex chromosomes causes abnormal distribution.
146
obligate carrier - carries gene but doesn't have trait
clear with dot in middle
147
asymptomatic carrier
clear with diagonal slash
148
(pedigree) autosomal recessive traits
appear equally in males and females and skip generations, and are more likely to appear in progeny of related parents
149
(pedigree) autosomal dominant traits
appear equally in males and females, do not skip generations, unaffected persons don't transmit trait, affected persons have at least one affected parent
150
(pedigree) x-linked recessive traits
appear more commonly in males. affected male does not pass trait to sons, but can pass allele to daughter. daughter can pass allele to sons who are affacted.
151
(pedigree) x-linked dominant traits
do not skip generations. affected males pass the trait to no sons and all of their daughters. affected females (heterozygous) pass trait to half of all progeny
152
(pedigree) y-linked traits
only appear in males, and all male offspring are affected
153
trait is dominant if
2 affected individuals have unaffected offspring
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trait is recessive if
2 unaffected individuals have affected offspring
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if the trait is sex-linked recessive
affected females will give trait to all male offspring
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if the trait is sex-linked dominant
affected males will give trait to all female offspring
157
prenatal genetic testing
ultrasound, amniocentesis, chorionic villus sampling, maternal blood testing
158
preimplantation genetic testing
usually done in IVF
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postnatal genetic testing
Alzheimer's (APOE4), Breast Cancer (BRCA), Huntington's Disease
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studying twins can help
assess environmental factors
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concordance in twins is high for
heart attack, epilepsy, arthritis, MS
162
concordance in twins is low for
cancer, death by infection
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NASA's Twin Study
showed that gene expression, telomere dynamics, DNA disruption, carotid artery thickening, ocular changes, and some cognitive functions do not go back after 6 months.
