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Genetics Notes 1
NAME:________________________
DATE:___________
Vocabulary Terms
__________________or ______________- The genetic _____________ of _________________ from parent to
offspring, such as hair, eye, and skin color.
_________________ CHROMOSOME-A ______of _____________chromosomes in an organism, with _____
being inherited from each parent.
_________________- A chromosome that is ______ a ______ chromosome.
Let's Summarize:
Genotype- ____________________________________________
(usually abbreviated as 2 letters)
• TT = homozygous= _______________
• Tt = heterozygous= _______________
• tt = homozygous= _______________
_________________ INHERITANCE- a trait controlled by ____or more genes that may be on the _________or
on _______________chromosomes
Examples of polygenic inheritance: _____ color, skin color, and _________ group
___________- _____________forms of the same ________. Alleles for a trait are ____________ at
corresponding positions on ________________chromosomes called ______ (plural) or a locus (singular.).
When 1 allele masks (_________) the effect of another, that allele is called _____________ and the hidden
allele is called__________________.
• ________________ alleles are represented by a _______________letter
• ________________ alleles are represented by a _______________letter
Dominant Genes = one gene ________________ the other
What are _______________Genes?
• The gene that is ________________ by a dominant gene
• Recessive genes can only express themselves if _________ genes are recessive
What makes an organism the way that it is?
• _____________vs. ____________
__________ that are expressed through _________ can be ____________. Characteristics that are
_____________ through environmental influences, such as injuries or practiced skills, ___________ be
inherited.
Gregor Mendel (1822-1884)
• Austrian ________
• Called the “Father of ____________" for his study of the inheritance of 7 traits in _____ plants.
• The traits that Mendel chose to study were easily _______________ in ___ distinct forms.
EX.: ________ Height - tall vs. short
Pod Shape - round vs. __________
Flower _______ – white vs. purple
Seed Color – __________ vs. yellow
• The ________________ of Mendel's work was ____ recognized until the turn of the ____ century
• Its ______________ prompted the foundation of genetics.
Let’s REVIEW:
Genotype Symbol
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Genotype Vocabulary
Phenotype
Geneticists apply mathematical _______________of ______________ to Mendel’s laws of heredity in
order to ____________the results of simple genetic ___________.
Mendel’s laws of heredity are based on his ________________ ____________of observations of
________________of the inheritance of traits.
To see this we use a _____________ Square
Punnett Squares
• To complete a Punnett square, we use a __________ to ______________ each __________.
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We ____________the _______________ allele with a ____________ letter, and the _____________
allele is given the ________ letter but in_______________.
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For the pea plant flowers:
______________: purple color = ___
______________: white color = ___
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If ______ parents are____________, then purple colored parent must be _____ and the white colored
parent must be ____.
How can we predict these results?
We complete the possible combinations.
Homozygous-dominant
Homozygous-recessive
These results show that _____ the F1 (1st filial generation) offspring are all __________colored ___________.
_______% purple offspring
We can use another Punnett square to predict the F2 (2nd filial generation) offspring.
Heterozygous - hybrid
Heterozygous - hybrid
Phenotypic ratio ___:___
Genotypic ratio ___:___:___
The results are ____________mathematically the________, a __:__ ratio with ___% purple & ___% white
offspring
Codominance
• _____ all alleles are dominant and recessive.
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Some alleles are ___________ ________ and neither are ____________ by the other.
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Alleles which are equally strong are said to be "_________________".
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When both alleles are present, they are _______ _____________ in the phenotype.
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The __________ is a __________ of both alleles.
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When expressing codominant alleles, _________alleles are represented by ____________
_____________ letters.
Codominance: in humans
Blood Type:
________________ ratio 1:1:1:1
___ type A
___ type B
1 type ____
1 type ___
___ & ___ are equally strong.
___ is recessive.
_________ is type A
_________ is Type B
_________ is Type AB
_________ is Type O
Incomplete Dominance
• _______________ ______________is a situation in which one ____________ is not completely
dominant over ______________.
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Example: Pink flower resulting from a red parent and a white parent.
Incomplete Dominance: F1 generation
Homozygous
Homozygous
______ % pink offspring
Incomplete Dominance: F2 generation
Heterozygous
Heterozygous
A __:__:__ ratio with ___% red, ___% pink & ___% white offspring
Sex-Linked Traits
Boy or Girl? The ___ Chromosome “Decides”
What are Sex Linked Traits?
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In 1910, ___________ __________discovered traits linked to sex chromosomes in _______ ______.
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Some genes are ____________ to the ___ and ___ chromosomes
EXAMPLE: In humans, ________________and ____________ are found on the ___ chromosomes
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In ______, traits _____________ anytime present
In ___________, must have ____ genes to ______ trait
Children _________ baldness from their _________
Punnett Square: What sex will the offspring be?
___ % chance of a male or a female child.
Baldness is carried by the ___________
Phenotype:
____% bald males
____% bald carrier females
____% not bald males
____% non-carrier females
If _____ is bald, will you be _____?
Phenotype:
___% bald males
____% bald carrier females
What if _____ is bald?
Phenotype:
____% carrier females
____% bald males
Genetic Diversity
• The sorting and ________________of ________ in sexual reproduction results in a great
___________of gene _________________in the offspring of any 2 parents.
• Genetically diverse populations are ________ __________to ____________ changing environments.
• __________ variation within the species makes a population __________ __________to adaptation to
changes in the environment.
• ___________ populations around the world are in __________ because of _____________.
• There is very _________ genetic ___________ between any 2 individuals.
• This makes them __________ susceptible to ___________ & will likely lead to their _____________.
• Recombination and ___________ provide for genetic diversity.
• Inserting, deleting, or substituting DNA bases can __________ genes.
• An altered gene in a sex cell may be passed on to _________ cell that develops from it, causing an
altered ______________.
Crossing-over
• The physical _____________of chromosomal _________between chromatids of
__________________chromosomes.
• Result: Generation of _____ combinations of _________ (alleles).
• Occurs in ____________ of meiosis I
Creates chromosomes with _____ ____________ of _________ for genes
Sometimes ________chromosomes can be added or deleted, resulting in a genetic __________ such as
____________ 21 (Down syndrome).
Chromosomal Errors
• _________________: the __________of chromosomes to ___________properly in meiosis. Gametes
with _________or too ______ chromosomes result.
• Can cause diseases such as ___________ ________________.
• _________________: organisms with entire __________ _____ of chromosomes
• Results in the _________ of the fetus in _________
• Often occurs in _______and causes the ______and flowers to be _________. EX.: bananas, lilies
A ____________is an_____________, Arranged __________of _____________At Their Most Condensed State
Genetic Diseases
Turner's Syndrome
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__________ syndrome is a genetic disorder affecting _______ _________, in which the patient has __
X chromosome in some or all cells; or has two ___ ______________ but one is____________.
Signs of Turner syndrome include:
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_______ stature,
• delayed ________of the skeleton,
• ___________ fourth and fifth __________,
• broad ________,
• and sometimes _________ abnormalities.
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Women with Turner syndrome are usually _________ due to ovarian failure.
Diagnosis is by _________ test (karyotype).
Huntington’s Disease
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________________ disease (HD) is an inherited disorder caused by the ______________of certain
__________cells in the __________.
The gene for Huntington’s disease is _______________.
HD causes bizarre _____________movements and ______ of intellectual abilities (dementia).
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The condition begins most often in _____ - ____________and progresses _________ to ________.
The ________________of the codominant ______ for HD now makes it possible to ____________ who
will develop this disease by ____________their _____ from a blood sample in the laboratory.
Fragile X Syndrome
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An inherited disorder caused by a _____________ gene on the ___ chromosome.
Symptoms of Fragile X Syndrome:
• Mental______________,
• _____________ testes,
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and ________ abnormalities in males
• and mild or ___ effects in ____________.
It is the ______ ___________ inherited cause of ________ retardation.
Cri-du-chat Syndrome
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Cri-du-chat Syndrome is a _______ genetic disorder due to a ___________ portion of chromosome #__.
Its name, meaning ____ _____in French, is from the distinctive ___________sound made by
_____________ with the disorder.
The disorder is characterized by:
• distinctive _________ features,
• _________ head size,
• low birth ________,
• _______ muscle tone,
• a round face,
• epicanthal ________,
• low set _______,
• facial asymmetry
• ____________mental ________________ is typical
Tay - Sachs disease
A hereditary disease that affects young __________almost exclusively of eastern European
___________descent, in which an ____________ _____________ leads to the accumulation of _____
in the _________ and nerve tissue.
Tay -Sachs results in:
• mental _____________,
• convulsions,
• ______________,
• and ultimately __________.
Pedigrees
• ____________charts show a ____________of the family of an individual.
• It can be used to ________the _______________of a hereditary condition.
• It is particularly useful when there are ___________ families and a good family record over
_____________ generations.
Ethical & Moral Concerns
• The potential for identifying and _____________ _____________ raises practical and ethical questions.
• ______________, a pseudo-science of selective _____________of____________, was a movement
throughout the twentieth century, worldwide as well as in _____________, that demonstrated a
____________of the principles of___________.
• Eugenics is a dangerous idea that subtly____________ ____________.
• __________ was a proponent of eugenics and tried to create a “_____________” race known as
the____________.
• ____________is another morally charged issue facing us today.
• Cloning is the production of ________________ ___________ cells and/or ____________.
• _______ was famous all over the world because of the way she was born, in _______. She was the
world's first cloned ____________.