Science of Genetics - Intro

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Dec 12, 2012 (4 years and 8 months ago)

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GENETICS

BIOL 3315
-
003


Dr Cédric Feschotte

Office: LS Rm B08

Office hours:

TUE 11:00

12:30 am

THU 5:00
-
6:30 pm


cedric@uta.edu

Complementary
textbook:


An Introduction to
Genetic Analysis

9th Edition (2007)

by Griffiths, Wessler,
Lewontin & Carroll

Publisher: Freeman



Complementary
textbook (2):


Genetics
-
from
genes to genomes

by
Hartwell et al.

2nd Edition (2004)

Publisher: McGraw
-
Hill



GENETICS BIOL 3315
-
501

Tentative schedule

11 parts

Part 1. The Structure of Genes and Genomes (Chapter 2 in
textbook)

Part 2. Gene Function (Ch. 3)

Part 3. The Transmission of DNA at Cell division (Ch. 4)

Part 4. The Inheritance of Single
-
gene Differences (Ch. 5)

Part 5. Recombination in Eukaryotes (Ch. 6)


EXAM 1 (around week 5/6)


Tentative schedule
-

2:

Part 6. Recombinant DNA and Genetic Engineering (Ch. 7 + 8)

Part 7. Genomics and Bioinformatics (Ch. 9)

Part 8. Model Organisms and Genetic Screens (various
chapters, mostly Ch. 9 and 12)


EXAM 2 (around week 9/10)


Part 9. Mutations, Repair and Chromosome Dynamics (Ch.10+11)

Part 10. The Regulation of Gene Expression (Ch. 13)

Part 11. Population and Evolutionary Genetics (Ch. 17 and 19)



COMPREHENSIVE

FINAL EXAM (final’s week)




GENETICS
BIOL 3315
-
501

Grading policy:

Exam I 30%

Exam II 30%

Final exam 35%

Participation 5%


Letter grades will be assigned on a curve, but the
standard categories (i.e., 90+ = A, etc.) serve as
defaults.




How to study and be successful in this course?

1.
Before each lecture:

read

book chapter (or part of chapter)
corresponding to forthcoming lecture

2.
Before each lecture:

Print and browse through
slides


3.
Attend all lectures
, take
notes

and ask

questions

during
lecture

4.
After each part/section is complete:
read again

entire
chapter in book, review slides/notes and
write a summary
of what we’ve seen in class
(not the book’s chapter)

5.
DO THE

PROBLEMS

in the book and online!

Interactive
‘unpacking the problems’, practice test and extra material
are at
http://bcs.whfreeman.com/mga2e/

6.
Ask for extra support and further info to
Genetics
clinic/tutors
(Tutors’ schedule will be available next week)

Register and send your
quiz results to
cedric@uta.edu

Where to find the class notes:

Click on ‘teaching’

Bookmark this page:
http://www3.uta.edu/faculty/cedric/3315.HTM


GENETICS
BIOL 3315

A brief introduction





Experimental science
of heredity


Gregor Mendel
:

Discovered principles

of heredity (mid 1800’s)




What’s Genetics?

Mendel’s first experiment




Grew out of need of plant and animal
breeders

for
greater understanding of inheritance of economically
important characters



Today, genes are explained in
molecular terms




Genetics and genomic research are fields of major
importance for
medicine

The Science of Genetics

Physical and chemical basis of heredity


Genome
: basic complement of DNA of an organism


haploid: one copy of the genome (e.g. fungi, algae,
bacteria)


diploid: two copies of the genome (e.g. plants,
animals)



Genome contains all
GENES

and their regulatory
sequences






GENOME

Cell

Chromosome

Genes

DNA

Regulatory
network

The genome holds the master blueprint of life

Proteins +
ncRNAs

mRNA

mRNA

ncRNA

transcription

translation

Is there a (good)
definition for a gene?

Not really

ENCYCLOPÆDIA BRITANNICA
:

Gene:

unit of hereditary information that occupies a fixed position (locus) on a
chromosome. Genes achieve their effects by directing the synthesis of proteins.
[Not
always Proteins; genes also encode functional non
-
coding RNA, plus genes do not
always occupy a fixed position, some may be mobile, ‘jumping genes’



Wikipedia:

A pretty good definition

Genes

are the units of heredity in living organisms. They are encoded in the organism's
genetic material (
usually DNA or RNA
), and control the physical development and
behavior of the organism.

Note: The term "gene" is shared by many disciplines, including classical
genetics, molecular genetics, evolutionary biology and population
genetics. Because each discipline models the biology of life differently,
the usage of the word gene varies between disciplines. It may refer to
either material or conceptual entities.

Gene: some definition
s

Lifescience dictionary:

(my personal favorite)

Gene:

The fundamental physical and functional unit of heredity. A gene is an ordered
sequence of nucleotides located in a particular position on a particular chromosome
that encodes a specific functional product (i.e.,
a protein

or RNA molecule
).

Example of a bad definition

Gene
:

an ordered sequence of DNA located in a
particular position on a particular chromosome that
encodes a specific functional product (i.e., a protein
or RNA molecule).



Note
:



many different genes on each chromosome



homologs: chromosomes carrying the same genes



in diploids, one homolog inherited from each parent



Physical and chemical basis (cont’d)


DNA
:

complementary polynucleotide chains


A
-
T and G
-
C base pairs


Double
-
helix


RNA
:
single
-
stranded polynucleotide chain

encoded by DNA,
mutliple functions, including template for protein synthesis
(mRNA)


Protein



Encoded by messenger RNA


linear chain of amino acids (polypeptide)


encoded by gene


subject to variation that occur in coding DNA (mutations)


folds into 3 dimensional structure


may associate with other proteins to form a functional
complex






The ‘Central Dogma’ of Molecular Biology

From gene to protein:

Genetic variation


Alleles


alternative forms of a gene, typically each form
encodes protein with different amino acid
sequence


located at same position (
locus
) on a given
chromosome


Phenotype:

appearance or physiological expression
of gene


Genotype:

‘sum’ of all alleles present in individual
(up to 2 if organism is diploid)

Genetic variation



Mutants
: rare, exceptional variants of a gene which
generally alters protein function and consequently
the phenotype


normal phenotype called
wild
-
type


Alleles arise through
mutation

= DNA change


Polymorphism
: sites of changes in alleles of the same
gene within a population or species (e.g. single
nucleotide polymorphisms, SNPs)