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120 Cards in this Set

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autosomal recessive?
when carriers are both male and female
if there are carriers, what is it?
recessive
if there are not carriers, what is it?
dominant
x-linked recessive?
carriers are only female
y-linked dominant
all males, no carriers
x-linked dominant
no carriers, dad has, and so do all daughters
autosomal dominant
no carriers, dad has, daughters don't
mitochondrial
affects both males and females

females transmit it to offspring
5 types of pedigrees
autosomal recessive, x-linked recessive, y-linked, autosomal dominant, x-linked dominant
what do both copies of the chromosome need for it to show?
both need the trait
examples of autosomal recessive
deafness, albinism, cystic fibrosis
examples of x-linked recessive
color blind, hemophelia, muscular dystrophy, male pattern, baldness
where is the allele missing x-linked recessive
y
where is the trait present?
male
examples of y-linked disorders
hairy ears, sawyer's syndrome
examples of autosomal dominant
huntington's, dwarfism
examples of x-linked dominant
manic depression
why can only females transmit it to offspring?
mitochondria have their own DNA and therefore are not coded for in our 23 pairs of chromosomes
how are mitochondria passed to offspring?
via the cytoplasm of the egg
when is the cytoplasm of the sperm lost
during maturation
what causes variations in gene expression
temperature and age
explain temperature and how it causes variation in gene expression
some genes will only be expressed during certain temp ranges
example of temperature causing variations in gene expression
epidermolysis bullosa
explain age and how it causes variations in gene expression
the phenotypic expression of some genetic disorders are delayed until adulthood
example of age causing variations in gene expression
huntington disease, ages 30-50
what are the aspects of variation in gene expression
penetrance and expressivity
what is penetrance and how does it relate to aspects of variation in gene expression
the probability that a disease phenotype will appear when a disease-related genotype is present
what is penetrance influenced by
environmental factors
what is expressivity and how does it relate to aspects of variation in gene expression
refers to the range of phenotypes resulting from a given genotype

defines the degree of expression for a given trait
why do some genes fail to independently assort
because of linkage
what is linkage
when genes on the same chromosomes are inherited together
can we determine if certain genes will be linked?
yes
how can we determine if certain genes will be linked
recombination frequencies that can be used to construct genetic maps
what do genetic maps do
they define all the locations of the loci on the chromosome
what can a lod score measure?
linkage and recombination
what does the lod method do
uses probability techniques to determine whether genes are linked
what are lod scores
the result ratios that are created when analyzing the lod method results
what happens if the lod scores are 3 or greather
the loci in question are known to be linked
how is phenotypic variation measured?
heritability
what is heritability
an expression of how much of the observed variation in a phenotype is due to differences in genotype
what factors attribute to differences in heritability
genotype variance and environmental variance
heritability is a population phenomenon that applies to
groups, not individual
what is genetic relatedness used to create
heritability estimates
why are multifactorial traits and heritability difficult to study?
interaction between genes and environments
what is dermatoglyphics
the study of skin ridges on the fingers, palms, toes, and soles
how is dermatoglyhics used to study heritability
they develop during the first three months of the embryonic development
what are the two types of twins
monozygotic (MZ) and dizygotic (DZ)
monozygotic (MZ) twins
identical and share the same genotype and sex
when will the environment differ in monozygotic twins
if separated at birth and raised in different environments
dizygotic (DZ) twins
not identical
when do twins show concordance
if both have a trait
when do twins show disconcordance
if only 1 twin has a trait
what was studied in twins in 1916 to look for concordance
obesity
what plays an important role in obesity
heredity
what can polygenetic inheritance account for
body mass ranging from thin to obese
how does DNA control obesity
the obese gene encondes a weight-controlling hormone called leptin

leptin moves through the blood to the hypothalamus in the brain, which regulates fat conversion and the rate of energy consumption
polygenic trait
a phenotype resulting from the action of two or more genes
multifactorial traits
traits that result from the interaction of one or more environmental factors and two or more genes
genetic variance
the phenotypic variance of a trait in a population that is attributed to geetic differences
dermatoglyphics
the study of the skin ridges on the fingers, palms, toes, and soles
concordance
agreement between traits exhibited by both members of a twin pair
atherosclerosis
arterial disease associated with deposition of plaques on the inner surface of blood vessels
discontinuous variation
phenotypes that fall into two or more distinct, nonoverlapping classes
regression to the mean
in a polygenic system, the tendency of offspring of parents with extreme differences in phenotype to exhibit a phenotype that is the average of the two parental phenotypes
environmental variance
the phenotypic variance of a trait in a population that is attributed to exposure to differences in the environment by members of the population
monozygotic twins
twins derived from a single fertilization event involving one egg and one sperm, such twins are genetically identical
leptin
a hormone produced by fat cells that signals the brain and ovary
lipoproteins
particles with protein and phosphoipid coats that transport cholesterol and other lipids in the bloodstream
continuous variation
a distribution of phenotypic characters from one extreme to another in an overlapping or continuous fashion
heritability
an expression of how much of the observed variation in a phenotype is due to differences in genotype
correlation coefficient
a measure of the degree to which variables vary together
dyzgotic (DZ) twins
twins derived from two separate and nearly simultaeous fertilization events, each involving one egg and one sperm

such twins share on average 50% of their genes
hypertension
elevated blood pressure, consisting above 140/90 mm
familial
an autosomal dominant condition associated with one development of growths known as polyps in the colon. These polyps often develop into malignant growths, causing cancer of one of the colon and/or rectum
cystic fibrosis
a fatal recessive genetic disorder, common in the U.S. white opulations, associated with abnormal secretions of the exocrine glands
hemizygous
a gene present in a single dose on the x chromosome that is expressed in males in both the recessive and dominant condition
y-linked
genes located only on the y chromosome
penetrance
the probability that a disease phenotype will appear when a disease-related genotype is present
genetic map
the arrangement and distance between genes on a chromosome, deduced from studies of genetic recombination
sickle cell anemia
a recessive genetic disorder associated with an abnormal type of hemoglobin, a blood transport protein
hypophosphatemia
an x-linked dominant disorder

those affected have low phosphate levels in blood and skeletal deformities
huntington disease
an autosmoal dominant genetic disorder characterized by involunary movement of the limbs, mental deterioration, and death within 15 years of onset

symptoms appear betwen 30-50 years of age
expressivity
the range of phenotypes resulting from a given genotype
ABO groups
three alleles of a gene on human chromosome 9 that specify the presence and/or identity of certain molecules on the surface of red blood cells
marfan syndrome
an autosomal dominant genetic disorder that affects the skeletal system, the cardiovascular system, and the eyes
color blindness
defective color vision caused by reduction or absence of visual pigments

3 forms - red, green, and blue
porphyria
a genetic disorder inherited as a dominant trait that leads to intermittent attacks of pain and dementia, with symptoms first appearing in adulthood
camptodactyly
a dominant human genetic trait that is expressed as immobile, bent little fingers
lod method
a probability technique used to determine whether genes are linked
x-linkage
the pattern of inheritance that results from genes located on the x chromosomes
muscular dystrophy
a group of genetic diseases associated with progressive degeneration of muscles

duchenne & becker muscular dystrophy are inherted as x-linked, allelic, recessive traits
linkage
a condition in which two or more genes do not show independent assortment

they tend to be inherited together
lod score
the ratio of the probability that two loci are linked to the probability that they are not linked, expressed as the log10

scores of 3 or more are taken as establishing linkage
most common form of color blindness
red-green
what type of inheritance is red and green color blindness
x-linked recessive traits
what type of inheritance is blue color blindness
autosomal dominant
maps to chromosome 7
what type of inheritance is muscular dystrophy
autosomal and x-linked
what is the most common type of muscular dystrophy
duchenne
what type of inheritance does duchenne have
x-linked
what is the first signs of DMD
progressive muscle weakness
what is becker (muscular dystrophy)
a shortened dystrophin that is partionally functional
what is a cure for muscular dystrophy
dystrophin gene
what is sickle cell anemia
abnormal type of hemoglobin
blood vessel blockage
early death
what is hemoglobin
protein found in red blood cells that transports oxygen from the lungs to the tissues of the body

(lethal, affected die in childhood)
what type of disorder is sickle cell anemia
recessive
what type of disorder is porphyria
autosomal dominant
what is porphyria
mobility to correctly metabolize porphyrin
what is porphyrin
chemical component of hemoglobin
symptoms of porphryia
seizures, wine-colored urine, intense physical pain, dementia, pschors, episodes of mental derangement
characteristics of cystic fibrosis
mucous production that blocks ducts of certain glands, lung passages, often fatal by early adulthood
what type of disorder is cystic fibrosis
autosomal recessive
symptoms of cystic fibrosis
thick mucus, malnutrition, lung diseases, premature death
characteristics of comptodactyly
stiff, permanently bent little fingers

improper attachment of muscles to bones in the litle finger

both, one, neither - both hands
Huntington Disease characteristics
progressive degeneration of nervous system, dementia, early death

mental deterioration and uncontrolled jerky movements of the head and limbs
what type of disorder is huntington disease
autosomal dominant
what type of disorder is marfan syndrome
autosomal dominant
characteristics of marfan syndrome
connective tissue defect
death by aortic rupture
chromosome 15
what's affected in marfan syndrome
skeletal system, eyes, cardiovascular
affected of marfan syndrome tend to
have long arms an legs, long thin fingers, and tend to be tall and thin
what is the most dangerous in marfan syndrome
cardiovascular -> aorta