This is the Fall 03 semester' This course is Biol' 2004, GENETICS' CRN 90729' We meet T,R 3:30 4:45

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This is the Fall 03 semester. This course is
Biol. 2004, GENETICS. CRN 90729. We meet
T,R 330 - 445 in room NOR 136. My name is
B.J. Turner. I am an Assoc. Prof of Biology
and an evolutionary geneticist. I am your
instructor for this course. I have been
teaching genetics since 78, when I joined this
faculty. My office hours are W,F 1000 - 1130
AM. My office is 2113D Derring. If you come
to my office hours any time up to one day
before an exam, I will give you a free
chocolate chip cookie. Yes, this is a bribe I
am happy to meet with you at other times by
appointment. My e-mail is fishgen_at_vt.edu.
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The prerequisites for this course are a year of
Intro. Biology and a year of General Chemistry.
If you have not completed these courses please
reconsider your enrollment. This course is NOT
recommended for freshman students unless they
have an unusually strong background in biology.
If you believe you have such a background, please
see me after class today. Some freshmen with
strong academic skills do earn good grades in
this course. At this time, this class is full,
and force adds are not being accepted. This may
well change during the first couple of weeks in
the semester.
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The textbook is Essentials of Genetics, 4th ed.
By Klug Cummings. The book is supported by a
CD, but it is not yet widely available on campus.
The publisher also has a webpage for the text,
and the url and passwords will be distributed
when they arrive on campus.
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Much of the material presented in the first few
weeks of this course reviews and develops
concepts that should be already familiar to you
from your Introductory Biology course. It is a
very good idea at this point to re-read the
appropriate sections of the textbook you used in
Intro. Biology.
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There will be a class webpage that will have the
slides for each lecture. The slides will
usually be posted after the lecture. These
slides are good study material, but you should
also read the textbook and take notes from the
lecture. A good way to study for this course
is to retype your classnotes after every
lecture. That way, you will quickly identify
things you missed or which you found
confusing. Studying with other students can
helpful, but only if the group includes at least
one strong student. The least effective way to
study for this course is to just use a
highlighter when reading the text. Highlighting
has its place, but I know many students who
have done poorly with a text full of yellow
lines. Dont fool yourself. In grading, I will
reward command of the material on a conceptual
level. I have little use for straight
memorization.
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There will be informal weekly recitation
sections, probably on Weds evenings. Time and
place will be announced. There will be evening
review sessions before each class exam and one
in class before the Final exam. Questions from
previous exams will be given out and posted
on the webpage. These will be good study
tools, but you should not rely on them too
much. Exams will be multiple choice format,
but this does not mean that they will be
easy. Many of my questions incorporate two
or more concepts. They are not based on
recognition only.
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• Grade Computation
• Three class exams 10 lowest score. 25 each
  for the two highest scores. (60 total)
• 10 surprise class exams
• Final Exam (comprehensive) 30
• Note All exams adjusted to a mean of 70.

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I respect and use the honor system. I am
usually an easy- going person, but I will
unhesitatingly prosecute cheaters, and I have
done so in the past.
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Some excellent examples of specific genetic
phenomena occur in our own species. These
include sickle cell disease, which illustrates
both pleiotropy and heterozygote advantage, and
Tay-Sachs disease, which is a good example of a
recessive near-lethal gene with a known
physiological basis. Many of these
genes occur disproportionately in one or a few
ethnic or racial groups. For example, sickle
cell disease is in high frequency in Blacks of
West African descent, and Tay-Sachs disease
occurs very typically in Askenhazaic Jews who
lived in small communities in Russia, Lithuania
or Poland (my own ethnic background) .

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These observations are simple facts. They
carry no implications of racial or ethnic
inferiority. My use of these examples stems
from my attempt to be as effective an instructor
as I can. In no sense do they imply any ethnic
or racial bigotry on my part or on the part of
the geneticists who study them. Please note
that while various human groups do have
some specific traits at high frequencies, in
quantitiatve terms almost all (gt 97) of the
genetic variation in our species occurs among
individuals. Put another way, two individuals of
different races are likely to be no more
different genetically than two individuals of the
same race, on average. This observation has not
(yet) been assimilated into popular culture.
There is no genetic rationale for the
recognition of human races.
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Selective breeding was a powerful genetic
technique long before recombinant DNA was ever
thought of. It pre-dates formal genetics by
thousands of years
All of these food plants were selected from the
same species, the wild mustard. That plant has
little food value but may have been harvested in
times of famine or perhaps cultivated at first as
a medicinal herb.
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This is a naturally occurring plant called Queen
Annes Lace. It is the ancestor of a common food
item. Can you guess which food item was
selectively bred from this species?
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Unfortunately, genetics does not have
completely clean hands from a moral
perspective. In the 1920s and 30s, some
geneticists, often acting from a combination of
sincerity and bigotry, provided what they thought
was a genetic rationale for eugenics. Hopefull
y, we have learned from the mistakes of the past.
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Some resemblances are remarkable, but have little
to do with genetics
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FUNDAMENTAL CONCEPTS OF GENETICS 1. Genetic
information is the basis of genealogical
continuity, evolutionary change, physiological
function and development.
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• FUNDAMENTAL CONCEPTS OF GENETICS
• Genetic information exists at particular places
  on
• chromosomes, that is, it has a physical
  basis.
• The behavior of chromosomes during sexual
  exchanges
• between organisms provides bases for
  making
• predictions about the pattern of
  inheritance of traits.

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• FUNDAMENTAL CONCEPTS OF GENETICS
• The physical basis of genetic information is a
  nucleic acid, almost always DNA. The sequence of
  nucleotides in a particular DNA molecule is its
  information content

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• FUNDAMENTAL CONCEPTS OF GENETICS
• The nucleotide sequence of a DNA molecule
  is
• reproduced by a cellular process,
  replication.
• The fidelity of replication is the basis of
  genealogical
• continuity on both cellular and organismal
  levels.
• Infrequent errors in replication -
  mutations - are the
• bases of evolutionary changes.

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• FUNDAMENTAL CONCEPTS OF GENETICS
• The amino acid sequences of proteins, usually
  enzymes, indirectly determine traits and are the
  bases of biological function. These sequences
  are encoded in the nucleotide sequences of DNA.
• Information is transferred from DNA to
  protein by a two step
• process.
• In the first step, the information is
  transcribed into RNA.
• In the second, it is translated into amino
  acid sequences.

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The flow of information is summarized as
follows DNA -gt RNA -gt Protein
(DNA makes RNA makes protein ) The
central dogma of molecular biology.
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FUNDAMENTAL CONCEPTS OF GENETICS 6.
Development is a sequential pattern of
differential gene expression. That
is, the process is epigenetic and not
based on preformed structures.
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Lets take a breakplease
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• SOME QUESTIONS TO TEST YOUR KNOWLEDGE
• When does DNA replication occur during the
  process of cell division?
• When does it occur during meiosis?
• What is the difference between a chromosome and a
  chromatid?
• When does a chromatid become a chromosome?
• How do mitosis and meiosis differ?
• 6. What is synapsis, where does it occur, and
  what is its significance?
• 7. What properties determine if chromosomes
  synapse?
• 8. What are chiasma, where do they occur and
  what is their significance?

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• 9. What are tetrads, dyads and monads?
• What is a bivalent.
• 11. How does the behavior of chromosomes
• during meiosis explain Mendelian
  inheritance?

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A bivalent or tetrad
chiasmata (pl)
chiasma
chromatids
2 homologous chromosomes at synapsis
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Some terms to think about N the number of
chromosomes in the gametes of a particular
organism. The haploid number. 2N the number
of chromosomes in the somatic cells of a
particular organism. The diploid number. C
the amount of DNA in the gametes of a
particular organism.
Usually reported in picograms (10 -12 gm). 2C
the amount of DNA in the somatic cells of a
particular organism.
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How many chromosomes are there in a somatic cell
at mitotic prophase? What is the DNA content
of a somatic cell at mitotic prophase?
How many chromatids are there in a somatic cell
at mitotic prophase? How many centromeres
are there in a somatic cell at mitotic metaphase?
How would these answers change if the cell was
at mitotic anaphase? Telophase?
Early interphase (before S)?
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How many chromosomes are there in a somatic cell
at mitotic prophase? Ans. 2N What is the
DNA content of a somatic cell at mitotic
prophase? Ans. 4C How many chromatids are there
in a somatic cell at mitotic prophase? Ans.
4N How many centromeres are there in a somatic
cell at mitotic metaphase? Ans. 2N. How would
these answers change if the cell was at mitotic
anaphase? Telophase? Early interphase (before
S)?