LHydroptere is a large French trimaran with hydrofoils that is capable of up to 40 knots' - PowerPoint PPT Presentation

Title: LHydroptere is a large French trimaran with hydrofoils that is capable of up to 40 knots'


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LHydroptere is a large French trimaran with
hydrofoils that is capable of up to 40 knots.
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Small classes with outstanding faculty
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Open-ended investigations in lab and field
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• An Honors Program, not just a section

• A small group, excellent students, a special
  curriculum

• Regardless of career goals or future plans
• Research
• Med School, Vet School, Professional Schools
• Conservation biology, industry

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• Applications and Interviews - SOON
• Attend an information open house
• Feb 8 (Thursday) or Feb 13 (Tuesday)
• 408 Natural History Building
• 7-9 pm
• Sign up for an interview
• Applications at the info sessions
• email ibhonors (_at_life.uiuc.edu) for more
  information

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BIOLOGY RESEARCH SYMPOSIUM
Illini Biological Societys

• Interested in working in a campus research lab?
• Come learn about the benefits and available
  undergraduate and graduate research opportunities
  at UIUC!

February 7th, 7PM, 217 Noyes
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Lecture 8 Genetics Simple inherited patterns
of variation
Text Reading Chapter 14, up to 14.2
You need to be able to explain the following to
yourself and to me (on exams)
Describe the sex life of a pea plant carpel
stamens self-pollination cross-pollination
true-breeding hybridization List some of the
heritable traits of pea plants studied by
Mendel flower color seed shape seed color pod
shape pod color stem length flower
position Mendels Law of Segregation tracking
heritable traits for three generations parental
generation F1 generation F2 generation,
segregation, allele, dominant, recessive,
phenotype, genotype
 Probability multiplicative rule additive
rule Mendels Law of Independent
Assortment independent assortment of genes,
independent assortment of chromosomes Mendel in
the 21st century the plant growth hormone
gibberellin
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Figure 14.1 Gregor Mendel and his garden peas
The Field Museum has an exhibit on Mendel through
April 1.
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Table 14.1 The seven variable characters of pea
plants studied by Mendel.
Traits of pea plants flower color flower
position seed color seed shape pod shape pod
color stem length
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Figure 14.2 Research Method Crossing Pea
Plants(Note for genetic purposes we can often
treat plants like animals, without worrying about
alternation of generations).
The pea plant life cycle self-pollination cross-po
llination true-breeding
Peas normally self-fertilize - pollen (containing
sperm) fertilizes an ovum from the same plant,
or same flower in this case. Mendel manipulated
flowers to ensure cross-fertilization
(hybridization).
Plants that have selfed for several generations
are true-breeding - no variation.
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Figure 14.3 When F1 pea plants with purple
flowers were allowed to self-pollinate, what
flower color appeared in the F2 generation?
Law of Segregation three generations
segregation dominant, recessive phenotype,
genotype
EXPERIMENT True-breeding purple-flowered pea
plants and white-flowered pea plants were crossed
(symbolized by ?). The resulting F1 hybrids were
allowed to self-pollinate or were
cross- pollinated with other F1 hybrids. Flower
color was then observed in the F2 generation.
RESULTS Both purple-flowered plants and
white- flowered plants appeared in the F2
generation. In Mendels experiment, 705 plants
had purple flowers, and 224 had white flowers, a
ratio of about 3 purple 1 white.
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Figure 14.4 Alleles, alternative versions of a
gene
Law of Segregation three generations
segregation dominant, recessive phenotype,
genotype
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Figure 14.5 Mendels law of segregation
Law of Segregation three generations
segregation dominant, recessive phenotype,
genotype
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Figure 14.5 Mendels law of segregation
Law of Segregation three generations
segregation dominant, recessive phenotype,
genotype
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Figure 14.6 Phenotype versus genotype
Law of Segregation three generations
segregation dominant, recessive phenotype,
genotype
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Figure 14.7 The Testcross
Law of Segregation three generations
segregation dominant, recessive phenotype,
genotype
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Table 14.1 The seven variable characters of pea
plants studied by Mendel. Now note how all 7
show the same 3 to 1 ratio in the F2. Mendel was
generalizing, an important aspect of science.
Traits of pea plants flower color flower
position seed color seed shape pod shape pod
color stem length
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Heredity and Probability
Probability concepts multiplicative rule additive
rule
Same laws that apply to coin tosses, dice rolls,
card frequencies Each toss or roll is
independent Probabilities range between 0 and
1 MULTIPLY individual probabilities to obtain
the overall probability of one or more events
occurring together - when there is an AND , use
the Rule of Multiplication ADD individual
probabilities to obtain the overall probability
of an event that can occur two or more different
ways - when there is an OR, use the Rule of
Addition
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Figure 14.9 Segregation of alleles and
fertilization as chance events. This is the
multiplicative rule, to be used when events are
independent. Also called the and rule.
Probability concepts multiplicative rule additive
rule
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Probability concepts multiplicative rule additive
rule
P (A and B) P(A) x P(B)
What is the probability that a woman who gives
birth 2 times will have 2 daughters?
P (first birth is a girl and second birth is a
girl) P (first birth is a girl) x P (second
birth is a girl)
Given that the probability of a daughter at any
birth is 1/2
P (A and B) 1/2 x 1/2 1/4
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Probability concepts multiplicative rule additive
rule
In a cross between two heterozygous tall pea
plants, what is the probability that an offspring
will be tall (TT OR Tt)?
Heterozygotes are Tt and tall TT homozygotes are
also tall tt homozygotes are short
P (tall) P (Tt or TT) P (Tt) P (TT) P (Tt
or TT) 1/2 1/4 3/4
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Figure 14.8 Do the alleles for seed color and
seed shape sort into gametes dependently
(together) or independently?
Independent Assortment genes chromosomes
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Figure 13.10 The independent assortment of
homologous chromosomes in meiosis
Independent Assortment genes chromosomes
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5 steps for solving genetic problems

• Figure out the genotypes of the parents.
• Work out the genotypes of the gametes.
• Randomly combine the gametes.
• Work out all the possible genotypes of the
  progeny.
• Work out the resultant phenotypic frequencies of
  the progeny.

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Mendels discoveries (1865)

• Alleles sexually reproducing diploid organisms
  have two copies of each gene, one from the father
  and one from the mother they may be the same or
  different
• Dominance if an organism has two different
  alleles, one may be fully expressed while the
  other has no effect (implies same phenotype may
  not be same genotype)
• The two copies of a gene in an organism become
  separated during gamete formation (Segregation)
• Different traits are inherited independently
  (independent assortment)
• Inheritance reflects the rules of probability

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Why was Mendel successful?

• Chose pea plants as his model organism
• Chose traits with distinctly different forms
• Followed traits for several generations
• Quantitative analysis of results
• Developed a model
• Published quickly

The Field Museum has an exhibit on Mendel through
April 1.
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Moving Mendel into the 21st century The
Mendelian gene that controls stem length in peas
is formally called Le. The two alleles are Le
and le le/le is a dwarf pea plant. This gene has
recently been identified and sequenced. A single
base change in the le allele changes a single
amino acid in the encoded proteins, which is an
enzyme that is part of the chain of reactions
that makes the plant growth hormone gibberellin.

21st Century Mendel
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21st Century Mendel
The chemical pathway for gibberellin synthesis.
Gibberellin is a growth hormone, synthesized in a
long series of steps, each made possible by a
specific enzyme encoded by a specific gene. (You
need to know every detail on this slide - NOT.)
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How does this work, in more detail
21st Century Mendel
Chemical Y
Chemical X
Gibberellin
Le makes a better enzyme 3, that makes a lot of
Gibberellin, and le makes much less. But the
heterozygous Le/le plant makes enough Gibberellin
to grow normally. Thus le is a recessive allele
because in the heterozygote its presence is
masked by the normal dominant allele. We only
realize that le is present when it becomes
homozygous. The same principal applies to most
recessive/dominant allele relationships the
dominant allele usually encodes a normal protein
and the recessive allele a somewhat or completely
defective protein.
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Lecture 8 Genetics Simple inherited patterns
of variation
Text Reading Chapter 14, up to 14.2
You need to be able to explain the following to
yourself and to me (on exams)
Describe the sex life of a pea plant carpel
stamens self-pollination cross-pollination
true-breeding hybridization List some of the
heritable traits of pea plants studied by
Mendel flower color seed shape seed color pod
shape pod color stem length flower
position Mendels Law of Segregation tracking
heritable traits for three generations parental
generation F1 generation F2 generation,
segregation, allele, dominant, recessive,
phenotype, genotype
 Probability multiplicative rule additive
rule Mendels Law of Independent
Assortment independent assortment of genes,
independent assortment of chromosomes Mendel in
the 21st century the plant growth hormone
gibberellin
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Go BEARS!

• Or COLTS!