Transcript SCIENCE 10 LIFE SCIENCE: GENETICS 

SCIENCE 10
LIFE SCIENCE:
GENETICS
Genome British Columbia, 2004
www.genomicseducation.ca
I. How does the genetic code relate to the
assembly of different proteins?
I. How does the genetic code relate to the
assembly of different proteins?
 Recall from the unit on the cell that all of its
activities are controlled by a nucleus.
I. How does the genetic code relate to the
assembly of different proteins?
 Recall from the unit on the cell that all of its
activities are controlled by a nucleus. This
nucleus contains DNA, deoxyribonucleic acid,
which contains the information necessary to
make a variety of proteins.
I. How does the genetic code relate to the
assembly of different proteins? (cont.)
 Proteins perform many functions in your
body, such as those found in your muscles
that allow you to move or those in your mouth
that breakdown the starch in bread.
I. How does the genetic code relate to the
assembly of different proteins? (cont.)
 Proteins perform many functions in your
body, such as those found in your muscles
that allow you to move or those in your mouth
that breakdown the starch in bread. These
proteins also perform and control many
functions within the cell, but are only made
when needed.
I. How does the genetic code relate to the
assembly of different proteins? (cont.)
 The instructions to make these proteins are
contained in the genetic code.
I. How does the genetic code relate to the
assembly of different proteins? (cont.)
 The instructions to make these proteins are
contained in the genetic code. This code
consists of four different molecules known as
bases that are grouped into triplets.
I. How does the genetic code relate to the
assembly of different proteins? (cont.)
 The instructions to make these proteins are
contained in the genetic code. This code
consists of four different molecules known as
bases that are grouped into triplets. Each
triplet codes for one of twenty amino acids,
the building blocks used to build these
proteins.
I. How does the genetic code relate to the
assembly of different proteins? (cont.)
Each triplet codes for one of twenty amino
acids, the building blocks used to build these
proteins. The DNA determines what amino
acids, how many of each amino acid, and the
order of these amino acids to use for each
protein.
I. How does the genetic code relate to the
assembly of different proteins? (cont.)
Each triplet codes for one of twenty amino
acids, the building blocks used to build these
proteins. The DNA determines what amino
acids, how many of each amino acid, and the
order of these amino acids to use for each
protein. It’s like writing sentences with three
letter words from a four letter alphabet.
I. How does the genetic code relate to the
assembly of different proteins? (cont.)
 A gene is a section of DNA that contains the
genetic code for a specific protein, so it can
determine how an organism appears and
functions.
II. How are the principles that govern the
inheritance of traits used to solve problems
involving simple Mendelian genetics?
II. How are the principles that govern the
inheritance of traits used to solve problems
involving simple Mendelian genetics?
What is inheritance?
II. How are the principles that govern the
inheritance of traits used to solve problems
involving simple Mendelian genetics?
What is inheritance?
• Inheritance is the transfer of characteristics
from parents to their offspring, such as hair,
eye, and skin colour.
II. How are the principles that govern the
inheritance of traits used to solve problems
involving simple Mendelian genetics?
What is inheritance?
• Inheritance is the transfer of characteristics
from parents to their offspring, such as hair,
eye, and skin colour. This explains why your
traits resemble your parents and brother/sister.
II. How are the principles that govern the
inheritance of traits used to solve problems
involving simple Mendelian genetics? (cont.)
Who was Mendel?
II. How are the principles that govern the
inheritance of traits used to solve problems
involving simple Mendelian genetics? (cont.)
Who was Mendel?
• Gregor Mendel (1822 – 1868) was an Austrian
monk who experimented with pea plants to
determine how seven different, easily observed
traits are inherited:
II. How are the principles that govern the
inheritance of traits used to solve problems
involving simple Mendelian genetics? (cont.)
Who was Mendel?
• Gregor Mendel (1822 – 1868) was an Austrian
monk who experimented with pea plants to
determine how seven different, easily observed
traits are inherited: seed shape and colour, pod
shape and colour, flower colour and location,
and stem length.
II. How are the principles that govern the
inheritance of traits used to solve problems
involving simple Mendelian genetics? (cont.)
What did we learn from Mendel’s experiments?
II. How are the principles that govern the
inheritance of traits used to solve problems
involving simple Mendelian genetics? (cont.)
What did we learn from Mendel’s experiments?
•
He realized that traits are inherited in
predictable phenotype ratios.
What did we learn from Mendel’s experiments?
• He realized that traits are inherited in predictable
phenotype ratios. The phenotype are traits of
organism observed in its appearance or
behaviour, which is determined by its genes.
What did we learn from Mendel’s experiments?
• He realized that traits are inherited in predictable
phenotype ratios. The phenotype are traits of
organism observed in its appearance or
behaviour, which is determined by its genes.
• A trait can have different forms if there are
different forms of a gene at the same position of
DNA, which are known as alleles.
What did we learn from Mendel’s experiments?
• If an organism has the same allele from each
parent, then it is homozygous and is called a
purebred.
What did we learn from Mendel’s experiments?
• If an organism has the same allele from each
parent, then it is homozygous and is called a
purebred. However, if it has a different allele
from each parent, then it is heterozygous and is
called a hybrid.
What did we learn from Mendel’s experiments?
• When he crossed a white–flowered plant with a
purple–flowered plant and then crossed two of
these offspring, he observed the following
results.
What did we learn from Mendel’s experiments?
• When he crossed a white–flowered plant with a
purple–flowered plant and then crossed two of
these offspring, he observed the following
results.

What did we learn from Mendel’s experiments?
• When he crossed a white–flowered plant with a
purple–flowered plant and then crossed two of
these offspring, he observed the following
results.
P generation

What did we learn from Mendel’s experiments?
• When he crossed a white–flowered plant with a
purple–flowered plant and then crossed two of
these offspring, he observed the following
results.
P generation

purebred parents
What did we learn from Mendel’s experiments?
• When he crossed a white–flowered plant with a
purple–flowered plant and then crossed two of
these offspring, he observed the following
results.
P generation

all purple
purebred parents
What did we learn from Mendel’s experiments?
• When he crossed a white–flowered plant with a
purple–flowered plant and then crossed two of
these offspring, he observed the following
results.
P generation
F1 generation
(first falial)

all purple
purebred parents
What did we learn from Mendel’s experiments?
• When he crossed a white–flowered plant with a
purple–flowered plant and then crossed two of
these offspring, he observed the following
results.
P generation
F1 generation
(first falial)

purebred parents
hybrid offspring
all purple
What did we learn from Mendel’s experiments?
• When he crossed two of these purple–flowered
hybrid offspring from the F1 generation, he
observed the following results.
What did we learn from Mendel’s experiments?
• When he crossed two of these purple–flowered
hybrid offspring from the F1 generation, he
observed the following results.

What did we learn from Mendel’s experiments?
• When he crossed two of these purple–flowered
hybrid offspring from the F1 generation, he
observed the following results.
F1 generation

hybrid offspring
What did we learn from Mendel’s experiments?
• When he crossed two of these purple–flowered
hybrid offspring from the F1 generation, he
observed the following results.

F1 generation
¼ white
hybrid offspring
¾ purple
What did we learn from Mendel’s experiments?
• When he crossed two of these purple–flowered
hybrid offspring from the F1 generation, he
observed the following results.

F1 generation
F2 generation
(second falial)
¼ white
hybrid offspring
¾ purple
What did we learn from Mendel’s experiments?
What did we learn from Mendel’s experiments?
• These results showed that each parent passed on a
single allele to the offspring, such that the seed and
the pollen only carry one allele each, not both.
What did we learn from Mendel’s experiments?
• These results showed that each parent passed on a
single allele to the offspring, such that the seed and
the pollen only carry one allele each, not both.
• It also showed that each trait is inherited separately
from each other, such that one trait did not affect
how another trait was inherited.
What did we learn from Mendel’s experiments?
• Finally, it showed that the dominant purple colour
masked or hid the recessive white colour.
What did we learn from Mendel’s experiments?
• Finally, it showed that the dominant purple colour
masked or hid the recessive white colour. For the
white colour to be observed, the flower must have
two alleles for the white colour, such that is must be
a purebred for this trait.
How can we predict these results?
How can we predict these results?
• We can use a Punnett square to determine
determined the probability, the chances of a
particular outcome.
How can we predict these results?
• To complete a Punnett square, we use a letter to
represent each trait.
How can we predict these results?
• To complete a Punnett square, we use a letter to
represent each trait. We represent the dominant
allele with a capital letter, and the recessive allele is
given the same letter but in lower case.
How can we predict these results?
• To complete a Punnett square, we use a letter to
represent each trait. We represent the dominant
allele with a capital letter, and the recessive allele is
given the same letter but in lower case. For the pea
plant flowers, the dominant purple colour = P and
the recessive white colour = p.
How can we predict these results?
• To complete a Punnett square, we use a letter to
represent each trait. We represent the dominant
allele with a capital letter, and the recessive allele is
given the same letter but in lower case. For the pea
plant flowers, the dominant purple colour = P and
the recessive white colour = p. If both parents are
pure bred, then purple coloured parent must be PP
and the white coloured parent must be pp.
How can we predict these results?
• To complete a Punnett square, we use a letter to
represent each trait. We represent the dominant
allele with a capital letter, and the recessive allele is
given the same letter but in lower case. For the pea
plant flowers, the dominant purple colour = P and
the recessive white colour = p. If both parents are
pure bred, then purple coloured parent must be PP
and the white coloured parent must be pp. To
predict the results of a cross, we insert the alleles
from each parent into the Punnett square.
How can we predict these results?
How can we predict these results?
P
p
p
P
How can we predict these results?
P
P
p
p
We complete the possible combinations.
How can we predict these results?
p
p
P
Pp
P
How can we predict these results?
p
p
P
Pp
P
Pp
How can we predict these results?
p
P
Pp
p
Pp
P
Pp
How can we predict these results?
p
P
Pp
P
Pp
p
Pp
Pp
How can we predict these results?
p
P
Pp
P
Pp
p
Pp
Pp
• These results show that all the F1 offspring are all
purple coloured hybrids.
How can we predict these results?
• We can use another Punnett square to predict the
the F2 offspring.
How can we predict these results?
• We can use another Punnett square to predict the
the F2 offspring.
How can we predict these results?
• We can use another Punnett square to predict the
the F2 offspring.
P
P
p
p
How can we predict these results?
• We can use another Punnett square to predict the
the F2 offspring.
P
p
P
PP
p
How can we predict these results?
• We can use another Punnett square to predict the
the F2 offspring.
P
p
P
PP
p
Pp
How can we predict these results?
• We can use another Punnett square to predict the
the F2 offspring.
P
P
PP
p
Pp
p
Pp
How can we predict these results?
• We can use another Punnett square to predict the
the F2 offspring.
P
P
PP
p
Pp
p
Pp
pp
How can we predict these results?
• The F2 offspring consist of:
How can we predict these results?
• The F2 offspring consist of:
1 PP
How can we predict these results?
• The F2 offspring consist of:
1 PP
2 Pp
How can we predict these results?
• The F2 offspring consist of:
1 PP
2 Pp
1 pp
How can we predict these results?
• The F2 offspring consist of:
1 PP: purple coloured
2 Pp
1 pp
How can we predict these results?
• The F2 offspring consist of:
1 PP: purple coloured
2 Pp: purple coloured
1 pp
How can we predict these results?
• The F2 offspring consist of:
1 PP: purple coloured
2 Pp: purple coloured
1 pp: white coloured
How can we predict these results?
• The F2 offspring consist of:
1 PP: purple coloured
2 Pp: purple coloured
1 pp: white coloured
¾ purple coloured
How can we predict these results?
• The F2 offspring consist of:
1 PP: purple coloured
2 Pp: purple coloured
¾ purple coloured
1 pp: white coloured  ¼ white coloured
How can we predict these results?
• The F2 offspring consist of:
1 PP: purple coloured
2 Pp: purple coloured
¾ purple coloured
1 pp: white coloured  ¼ white coloured
• The phenotype ratio for this generation is 3:1.
What are the other patterns of inheritance?
What are the other patterns of inheritance?
A.Incomplete Dominance
What are the other patterns of inheritance?
A.Incomplete Dominance
What happens when neither allele is dominant?
What are the other patterns of inheritance?
A.Incomplete Dominance
What happens when neither allele is dominant?
• If a parent has straight hair and the other parent
has curly hair, then they may have children with
wavy hair, an intermediate phenotype.
What are the other patterns of inheritance?
A.Incomplete Dominance
What happens when neither allele is dominant?
• If a parent has straight hair and the other parent
has curly hair, then they may have children with
wavy hair, an intermediate phenotype.
• This occurs when neither allele in a hybrid is
completely are not completely expressed, such
that neither allele can mask the other allele.
What are the other patterns of inheritance?
B. Codominance
What are the other patterns of inheritance?
B. Codominance
What happens when both alleles are dominant?
What are the other patterns of inheritance?
B. Codominance
What happens when both alleles are dominant?
• Depending upon what alleles you inherited from
each parent, you can have blood type:
A, B, AB, or O.
What are the other patterns of inheritance?
B. Codominance
What happens when both alleles are dominant?
• Depending upon what alleles you inherited from
each parent, you can have blood type:
A, B, AB, or O.
• If you inherited an allele for type A from one
parent and an allele for type B from the other
parent, then you would have type AB blood,
such that you are a hybrid expressing both
alleles.
What are the other patterns of inheritance?
C. Sex Linkage
What are the other patterns of inheritance?
C. Sex Linkage
Are there any traits related to an individuals sex?
What are the other patterns of inheritance?
C. Sex Linkage
Are there any traits related to an individuals sex?
• Of your 23 pairs of chromosomes, you have one
pair of sex chromosomes.
What are the other patterns of inheritance?
C. Sex Linkage
Are there any traits related to an individual’s sex?
• Of your 23 pairs of chromosomes, you have one
pair of sex chromosomes. Females have two X
chromosomes, while males have one X and one
Y chromosome.
What are the other patterns of inheritance?
C. Sex Linkage
Are there any traits related to an individual’s sex?
• Of your 23 pairs of chromosomes, you have one
pair of sex chromosomes. Females have two X
chromosomes, while males have one X and one
Y chromosome.
• Hemophilia is a disease where blood does not
properly clot and caused by a recessive gene on
the X chromosome.
What are the other patterns of inheritance?
C. Sex Linkage (cont.)
• If a male inherits a defective allele from his
mother, then he will have hemophilia because he
does not have second X chromosome with a
normal allele to mask this defective allele.
What are the other patterns of inheritance?
C. Sex Linkage (cont.)
• If a male inherits a defective allele from his
mother, then he will have hemophilia because he
does not have second X chromosome with a
normal allele to mask this defective allele.
• Although he will pass this allele onto his
daughter, she can only get this disease if she
inherits a defective gene from her mother.
III. What are factors that may cause mutation
III. What are factors that may cause mutations?
What is a mutation?
III. What are factors that may cause mutations?
What is a mutation?
• A change in a DNA sequence that occurs
naturally during cell division or results from an
environmental factor.
III. What are factors that may cause mutations?
What environmental factors cause mutations?
III. What are factors that may cause mutations?
What environmental factors cause mutations?
A. Chemical:
III. What are factors that may cause mutations?
What environmental factors cause mutations?
A. Chemical: Some toxins, such as PCBs
(polychlorinated biphenals), may react
chemically with DNA and cause cancer.
III. What are factors that may cause mutations?
What environmental factors cause mutations?
A. Chemical: Some toxins, such as PCBs
(polychlorinated biphenals), may react
chemically with DNA and cause cancer.
B. Biological:
III. What are factors that may cause mutations?
What environmental factors cause mutations?
A. Chemical: Some toxins, such as PCBs
(polychlorinated biphenals), may react
chemically with DNA and cause cancer.
B. Biological: Some viruses, such as HIV which
causes AIDS, infect host cells by inserting their
DNA in the host’s DNA.
III. What are factors that may cause mutations?
What environmental factors cause mutations?
C. Physical:
III. What are factors that may cause mutations?
What environmental factors cause mutations?
C. Physical: Radiation, such as UV light from
sunlight or X-rays from a dentist’s office,
directly damages the structure of DNA.
IV. What are the positive, neutral, and negative
effects of various mutations?
IV. What are the positive, neutral, and negative
effects of various mutations?
A. Positive:
IV. What are the positive, neutral, and negative
effects of various mutations?
A. Positive: If a mutation improves an organism’s
ability to survive or compete in its environment,
then this is a positive mutation.
IV. What are the positive, neutral, and negative
effects of various mutations?
A. Positive: If a mutation improves an organism’s
ability to survive or compete in its environment,
then this is a positive mutation.
For example, a mutation that allows a western
red cedar tree to grow faster may compete better
against other trees for sunlight.
IV. What are the positive, neutral, and negative
effects of various mutations?
IV. What are the positive, neutral, and negative
effects of various mutations?
B. Negative:
IV. What are the positive, neutral, and negative
effects of various mutations?
B. Negative: If a mutation reduces an organism’s
ability to survive or compete in its environment,
then this is a negative mutation.
IV. What are the positive, neutral, and negative
effects of various mutations?
B. Negative: If a mutation reduces an organism’s
ability to survive or compete in its environment,
then this is a negative mutation.
For example, a mutation that impairs a deer’s
vision will make it harder to see food and prey
clearly.
IV. What are the positive, neutral, and negative
effects of various mutations?
IV. What are the positive, neutral, and negative
effects of various mutations?
Another example is an albino, who has white
skin and hair.
IV. What are the positive, neutral, and negative
effects of various mutations?
Another example is an albino, who has white
skin and hair. Albinos cannot produce melanin,
which is the pigment that gives colour to our
skin, hair, and eyes and protects us from
ultraviolet light.
IV. What are the positive, neutral, and negative
effects of various mutations?
C. Neutral:
IV. What are the positive, neutral, and negative
effects of various mutations?
C. Neutral: If a mutation does not change an
organism’s ability to survive or compete in its
environment, then this is a neutral mutation.
IV. What are the positive, neutral, and negative
effects of various mutations?
C. Neutral: If a mutation does not change an
organism’s ability to survive or compete in its
environment, then this is a neutral mutation.
Most mutations do not affect an organism
because they do not significantly change the
proteins that are made.
IV. What are the positive, neutral, and negative
effects of various mutations?
C. Neutral: If a mutation does not change an
organism’s ability to survive or compete in its
environment, then this is a neutral mutation.
Most mutations do not affect an organism
because they do not significantly change the
proteins that are made.
For example, a mutation that turns a rose’s
colour from red to pink would not affect its
function.
IV. What are the positive, neutral, and negative
effects of various mutations?
IV. What are the positive, neutral, and negative
effects of various mutations?
The effects of a mutation are not always
obvious.
IV. What are the positive, neutral, and negative
effects of various mutations?
The effects of a mutation are not always
obvious. While a western red cedar that grows
faster can get more sunlight, it may be more
likely to suffer damage from strong winds.
V. What are the implications of current and
emerging biomedical, genetic, and
reproductive technologies?
V. What are the implications of current and
emerging biomedical, genetic, and
reproductive technologies?
biomedical,
genetics, and
reproductive
technologies
V. What are the implications of current and
emerging biomedical, genetic, and
reproductive technologies?
genetic probes
biomedical,
genetics, and
reproductive
technologies
V. What are the implications of current and
emerging biomedical, genetic, and
reproductive technologies?
genetic probes
genetic testing
biomedical,
genetics, and
reproductive
technologies
V. What are the implications of current and
emerging biomedical, genetic, and
reproductive technologies?
genetic probes
genetic testing
gene therapy
biomedical,
genetics, and
reproductive
technologies
V. What are the implications of current and
emerging biomedical, genetic, and
reproductive technologies?
genetic probes
genetic testing
gene therapy
biomedical,
genetics, and
reproductive
technologies
forensic science
V. What are the implications of current and
emerging biomedical, genetic, and
reproductive technologies?
genetic probes
genetic testing
gene therapy
biomedical,
genetics, and
reproductive
technologies
forensic science
drug development
V. What are the implications of current and
emerging biomedical, genetic, and
reproductive technologies?
genetic probes
genetic testing
gene therapy
biomedical,
genetics, and
reproductive
technologies
forensic science
drug development
drug production
V. What are the implications of current and
emerging biomedical, genetic, and
reproductive technologies?
genetic probes
genetic testing
gene therapy
cloning
biomedical,
genetics, and
reproductive
technologies
forensic science
drug development
drug production
V. What are the implications of current and
emerging biomedical, genetic, and
reproductive technologies?
genetic probes
genetic testing
gene therapy
cloning
biomedical,
genetics, and
reproductive
technologies
forensic science
drug development
drug production
GMOs
V. What are the implications of current
and emerging biomedical, genetic,
and reproductive technologies?
What is genomics and how will it affect my life?
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What are some current genetic research projects in BC?
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THE END
Genome British Columbia, 2004
www.genomicseducation.ca