Genetics exam 1 Flashcards
(169 cards)
0
Q
define the principle of random segregation
A
different alleles for a particular gene occupy the same locus on homologous chromosomes
1
Q
a cross between two parents that differ in a single characteristic is called?
A
a monohybrid cross
2
Q
What is a gene?
A
a genetic factor that helps determine a trait. DNA that is transcribed into RNA.
3
Q
What is an allele?
A
one of two or more alternate forms of a gene
4
Q
What is a locus?
A
specific place on a chromosome occupied by an Allele
5
Q
This term defines a set of alleles possessed by an individual organism
A
Genotype
6
Q
Heterozygotes can be defined as?
A
an individual organism possessing two different alleles at a locus
7
Q
An individual organism possessing two of the same alleles at a locus
A
homozygote
8
Q
The appearance of a given trait
A
phenotype
9
Q
Oculocutaneous albinism type 2 is due to a defect in the OCA gene on which chromosome?
A
Chromosome 15
10
Q
A genome is defined as a ?
A
complete set of genetic instructions for any organism either RNA or DNA.
11
Q
This subdivision of genetics encompasses basic principles of heredity and how traits are passed from one generation to the next.
A
Transmission Genetics
12
Q
This subdivision of genetics concerns the chemical nature of the gene itself and how genetic information is encoded, replicated, and expressed.
A
Molecular genetics
13
Q
This subdivision of genetics explores the genetic composition of groups of individual members of the same species and how that composition changes geographically and with the passage of time. It is fundamentally the study of evolution.
A
Population Genetics
14
Q
Genetic information travels from different parts of the body to reproductive organs (gemmules)
A
Pangenesis
15
Q
Inheritance of acquired characteristics proposes?…
A
acquired traits become incorporated into hereditary information.
ex: the blacksmith’s skills and upper body strength will be passed to his offspring.
16
Q
miniature organisms that reside in sex cells, and all traits are inherited from one parent is the concept of?
A
Preformationism
17
Q
When genes blend and mix
A
Blending inheritance
18
Q
The Germ-plasm theory explains that?
A
all cells contain a complete set of genetic information
19
Q
All life is composed of cells, and cells arise only from cells relates to which theory?
A
cell Theory
20
Q
Traits are inherited in accord with defined principles describes this concept?
A
Mendelian Inheritance
21
Q
The nucleus is present in Prokaryotic cells. T/F
A
false, the nucleus as well membrane bound organelles are absent.
22
Q
the short arm of a telocentric centromere is identified as? the long arm as?
A
short arm= p arm
long arm= q arm
23
Q
a diploid organism has two sets of chromosomes organized as?
A
homologous pairs
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the stable ends of a chromosome
telomeres
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a constricted region of the chromosome where the kinetochores form and the spindle microtubules attach
centromere
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This cellular process results in an increase in cell numbers and resulting daughter cells that are genetically identical
Mitosis
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Interphase has two checkpoints before mitotic division occurs. where are they?
G1-S checkpoint, cell is committed to dividing after this checkpoint
G2-M checkpoint, the cell can begin division
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a non-dividing phase in interphase
G0
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DNA synthesis, chromosome replication, inactive cdc2 kinase, B(M) cyclin concentration begins to increase at the end of this phase
S phase
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activated MPF in this phase leads to activities necessary for mitosis
G-2 phase
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Prior to S phase of the cell cycle, each chromosome consists of this many chromatids?
1 chromatid
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After S phase of the cell cycle, each chromosome consists of this many chromatids?
2- bound by a centromere
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in this phase, the nuclear membrane disintegrates and spindle microtubules attach to chromatids.
Pro-metaphase
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in this mitotic phase, the chromosome number has doubled and they have lined up along an equatorial plate
metaphase
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If cytokinesis does not occur there may be still be two nuclei, but they will be located in a single cell. resulting in an increase in ploidy. this is called?
Endomitosis
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in this phase, S cyclins bind to inactive cdc2 kinase and the cell is in growth and development
G-1
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these cells spend more time in the G-1 stage and grow and become differentiated. examples: hematopoietic cells, epithelial cells in the gut lining and the epidermis
Labile cells
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skeletal muscle cells, cardiac muscle cells, and neurons are classified as?
non-dividing cells
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the fusion of hapoid gametes
fertilization
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separation of sister chromatids occur in this stage of Meiosis. EQUATORIAL division.
Meiosis II
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separation of homologous chromosome pairs and REDUCTION of the chromosome number by half occurs in this stage of meiosis
Meiosis I
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pairing of homologous chromosomes is a major event in meiosis. this is celled?
Synapsis
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IF Crossing over happens in this stage of mitosis, where segments of non sister chromatids are exchanged.
Prophase I
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Independent assortment produces variation without?
crossing-over
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What are the five stages of Prophase?
1. Leptotene
2. Zygotene
3. Pachytene
4. Diplotene
5. Diakinesis
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when the synaptonemal complex forms because of the synapsis of homologous chromosomes (bivalents) the cell is in this stage of prophase?
Zygotene
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chromosomes are threadlike and begin to condense and become visible. The cell is in this stage of prophase?
Leptotene
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crossing-over begins and chromosomes become shorter and thicker
Pachytene
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Crossing-over continues and the Chiasmata is well-defined.
Diplotene
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when Crossing-over is completed and the nuclear membrane is disrupted, the cell is in this stage of prophase?
Diakinesis
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whats a Tetrad?
closely associated four sister chromatids of two homologous chromosomes
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when the kinetochores face opposite poles, the cell is in?
Metaphase II
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the end result for this stage is four genetically unique haploid daughter cells
Telophase II
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This protein holds chromatids together during early parts of mitosis and Meiosis.
Cohesin
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Cohesin at the centromere is protected by?
Shugoshin
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this enzyme breaks down Cohesin at the end of metaphase
Separase
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this protein keeps Separase inactive during interphase and early mitosis.
Securin
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Monopolins are proteins that keep sister kinetochores oriented (away or towards) the same pole during metaphase I?
toward
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Does random distribution of maternal and paternal chromosomes occur in Meiosis II?
no, only Meiosis I
60
oogenesis results in __ female gamete and spermatogenesis results in ___ male gametes
1,4
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Primary spermatocytes are haploid or diploid?
Diploid, they undergo meiosis I to produce haploid secondary spermatocytes.
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Spermatids differentiate into?
sperm
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Primary oocytes become locked in this stage of Prophase I?
Diplotene
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in most mammals, the egg is ovulated at this stage?
metaphase II
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up to three haploid small cells are each ootid (a haploid egg) can occur. these are known as?
Polar bodies
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the gametophyte stage in plants have a multicellular ___
haploid
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the Sporophyte stage in plants have a multicellular ___?
diploid
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two defective copies of the MC1R allele results in a person having this?
red hair.
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the Melanocortin-1 gene is located on this chromosome in humans
Chromosome 16
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increase in the production of Eumelanin gives offspring this hair color?
black or brown
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what is Pisum sativum?
the friggin Pea Plant!
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Mendel referred to the traits that appear unchanged in the heterozygous F1's as?
Dominant
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traits that disappeared in the F1 heterozygotes were termed?
recessive
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when two different alleles are present in a genotype, only the trait encoded by one of them- the dominant allele-is observed in the phenotype
The concept of dominance
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Monohybrid crosses are explained by?
the principle of segregation
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what is Mendel's first law?
principle of segregation
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Walter sutton contributed the?
chromosomal theory of heredity
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this man observed that each pair of homologous chromosomes consist of one maternal and one paternal chromosome and showed that homologous chromosomes segregate independently into gametes in meiosis
Walter Sutton
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Segregation results from?
the separation of homologous chromosomes in meiosis
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if no crossing-over takes place, the two chromatids of each chromosome segregate into anaphase II and are?
identical
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Independent assortment is which of Mendel's law?
the second law
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the key indicator "and" is most likely this rule when you calculate independent probabilities
Multiplication rule
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The probability of any two or more mutually exclusive events is calculated by adding the probabilities of these events. Key indicators= "either" and "or"
Addition rule. yay you!
84
a cross between an F1 genotype and either of two parental genotypes is a?
backcross
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a cross between an individual of unknown genotype and a homozygous recessive individual is a?
test cross.
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Dihybrid crosses illustrate this second mendelian law?
Principle of Independent assortment
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the Chi-square Goodness of Fit test indicates the probability that the difference between the observed and expected values is due to?
Chance
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Expected values are obtained by?
multiplying the expected proportion (%) by the total (#)
ex: 3/4 x 150= 112.5
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genotypic and phenotypic ratios are identical for?
incomplete dominance
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the production of both male and female gametes in the same individual.
monoecious
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the production of either male or female gametes in the same individual
Dioecious
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male and female sex determination is a characteristic of?
sexual phenotype
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both sexes in the organism describes this?
Hermaphroditism
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in the ZZ-ZW system, males express?
ZZ-homozygous
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birds, snakes, butterflies, fish, and some amphibians display this chromosomal sex determination system
ZZ-ZW
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Bees, wasps, and ants belong to this Chromosomal sex determining system
Haplodiploidy system
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in the Haplodiploidy system, males express this set while the females the other
Male-haploid set
Female- Diploid set
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Found in some plants, fungi, protozoans, and fish; this system only has the sex-determining genes but no sex chromosomes
Genic Sex-determining system
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Pseudoautosomal regions are regions where pairing occurs during meiosis, located?
at both tips of X and Y chromosomes- the short arm and the long arm
important in the MALE
100
the secondary pseudoautosomal region is located where on the chromosome?
the tip of the LONG arm
101
the primary pseudoautosomal region of the chromosome is located where?
the tip of the SHORT arm
102
ZW sex determination occurs in this gender?
the female
103
in Haplodiploidy, the males develop from?
UNFERTILIZED eggs and sperm are produced by MITOSIS. Somatic cells have a SINGLE set of chromosomes
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in haplodiploidy, the females develop?
FERTILIZED eggs and somatic cells have TWO sets of chromosomes
105
Genes at one or more loci determine the sex of the individual is a concept of? found in?
Genetic Sex-determining systems
plants and protozoans
106
Sequential hermaphroditism is an example of the "common slipper limpet" in this sex-determining system?
Environmental- where the males transform into females and mate with other males.
107
heterogametic sex in the XX-XO system is characteristic of which sex?
the male
108
Drosophila have how many chromosomes?
three pairs of autosomes and one pair of sex chromosomes
total of 8
109
does the presence of a Y chromosome determine maleness?
no. example, the Drosophila. each fly's sex is determined by balance between genes on autosomes and genes on the X chromosome in a Genic Balance System.
* X-female
* Autosome-Male
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XXX is expressed as this sexual phenotype
Metafemale
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XXY is expressed as this phenotype
female
112
XXXY is expressed as this sexual phenotype
metafemale
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three sets of haploid chromosomes with a sex chromosome complement of XX is expressed as this sexual phenotype
intersex
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three sets of haploid chromosomes with its sex chromosome complement XO is expressed as this sexual phenotype
Metamale
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three sets of haploid chromosomes with its sex chromosome complement XXXX is expressed as this sexual phenotype
metafemale
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what is the Sex determining region of the Y chromosome that causes neutral gonads to develop into testes?
sry gene
117
sry gene encodes a protein that binds to this complex molecule to cause a sharp bend in the molecule
DNA
118
the sry gene is located in this region of the chromosome?
the short arm
119
the androgen receptor is encoded by a gene on which chromosome?
the X chromosome
120
low hairline, broad chest, folds on neck, females with undeveloped sex characteristics, usually infertile, and a sex pair chromosome of XO in humans. this type of Androgen-sensitivity syndrome is known as?
Turner Syndrome
121
This syndrome usually affects males that have aneuploidy in their sex chromosomes. XXY, XXXY, XXYY. They present with small testes, reduced facial and pubic hair, and often taller than normal.
Klinefelter Syndrome
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the concept that the Barr body is an inactive X chromosome
Dosage Compensation
123
the number of Barr bodies correlate with the number of X chromosomes - 1. X-1=#of Barr bodies.
XXXY will have how many Barr bodies based on the above info?
2
124
X inactivation is brought about by the action of this? an RNA molecule
Xist- X inactivation specific transcript
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Xist RNA modifies Histones how?
methylation, deacetylation, and alteration of histone composition.
126
which region escapes X inactivation?
pseudoautosomal region
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X inactivation takes place in humans during the 3rd month of development. T/F?
false, occurs during the first few weeks
128
mutated CFTR causes chloride channels to remain closed which results in thick, sticky mucous on the apical surface of respiratory epithelial cells. This genetic disorder is known as? and which chromosome defect does it occur on?
Cystic Fibrosis. the long arm of Chromsome 7
129
at the Phenotypic level, heterozygotes produce both normal and mutated CFTR at the cellular level. These people would be Carriers of the gene. This is an example of?
Co-dominance
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if the phenotype of the heterozygote falls between (red, hot pink, pale pink, white) the phenotype range (red or white) of the two homozygotes, dominance is said to be?
Incomplete.
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Phenotypes of the Heterozygotes includes the phenotypes of both homozygotes
Codominance
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phenotype of the heterozygote is the same as the phenotype of ONE of the homozygotes.
Complete dominance
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the percentage of individuals having a specific genotype that express the expected phenotype
Penetrance
134
the degree to which a character is expressed
Expressivity
135
Human polydactyly exhibits?
incomplete penetrance and variable expressivity
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type O blood are the?
universal donors
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Type AB blood are the?
universal recipients
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B type blood produce which antigen and antibody type?
Antigen- B
Antibody-A
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if your body produces Anti A and Anti B, which blood type do you have?
Type O ii
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a person with type A blood received blood with A antibodies. will anything happen?
yes, the person received type B blood and the person is not compatible with the donation. the blood will clump together.
141
the masking of one gene by another gene at a different locus is called?
Epistasis
142
the gene that is masked is called the?
Hypostatic gene
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the gene that does the masking is called the?
Epistatic gene
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recessive epistasis refers to the presence of?
either two homozygous recessive genotypes that will mask the hypostatic gene.
145
homozygous dominant or heterozygous genotypes that mask the effects of the hypostatic gene is called?
Dominant epistasis.
146
how does the Bombay phenotype help explain epistasis?
people with the Bombay phenotype are homozygous for a recessive (h) mutation that fails to convert the intermediate into dominant (H). Type O blood can result from the masking of a terminal sugar on compound H or from the absence of compound H itself. Genotypes at both the H locus and the ABO locus determine the ABO blood type.
147
a duplicate recessive epistasis with a 9:7 ratio results in snails expressing?
Albinism
148
a ratio of 12:3:1 yields this type of interaction?
dominant epistasis.
149
recessive epistasis gives this ratio
9:3:4
150
a typical phenotypic ratio of 9:3:3:1 gives this type of interaction
no interaction takes place.
151
when does Complementation occur?
if an individual organism possessing two recessive mutations has a wild-type phenotype
ex:eye color in Drosophila
152
Sex-influence characters are determined by?
autosomal genes according to Mendelian principles. expressed differently in males and females
153
Sex-limited characters are determined by?
autosomal genes, expressed in only one sex, and have zero penetrance in the opposite sex
ex: cock-feathered males vs hen-feathered males.
154
Cock-feathering is an Autosomal dominant or recessive trait?
recessive
155
characteristics of these traits present in males and females, usually inherited from the maternal parent, exhibit extensive phenotypic variation, and the reciprocal crosses yield different results
Cytoplasmically inherited traits.
ex: stem and leaf color in the four'o clock plant
156
the genotype of the mother determines the phenotype of the offspring but not its own.
Genetic Maternal effect
157
Prader-Willi and Angelman syndrome are examples of this differential expression
Genomic Imprinting
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this mutation deletion in the long arm of Chromosome 15 is inherited from the Father
Prader-Willi Syndrome
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this mutation deletion is in the long arm of Chromosome 15 inherited from the Mother
Angelman Syndrome
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in Mammals, methylation is erased in Germ cells of each generation and then reestablished in the course of?
gamete formation
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sperm and eggs undergo different levels of ____, resulting in the differential expression of male and female alleles in the offspring.
methylation
162
human lgf2 locus is located on the?
short arm of Chromosome 11
163
Characteristics with only a few easily distinguishable phenotypes defines this term. "Qualitative"
Discontinuous Characteristics.
ex: tall vs short, red vs white
164
Characteristics by a continuous distribution of phenotypes. "Quantitative" often polygenic and or multifactorial
Continuous Characteristics
ex: human weight, human height, milk production in cattle, and Blood pressure in humans.
165
define polygenic characteristics
characteristics encoded by gene at multiple loci
ex:kernel color in wheat
166
characteristics that are polygenic and also influenced by environmental factors is? an example is Human intelligence
Multifactorial
167
Pleiotrophy is?
when one gene affects multiple characteristics
ex: recessive allele for phenylketonuria
168
Fragile X syndrome and Huntington disease are examples of?
Anticipation- related to expanding nucleotide sequences
