mors genetic mumbo jumbo

Environmental Expression of genes:


Certain genes are expressed under particular conditions, such as, temperature, geographic location, etc….


Examples: fruit flies….wings……temperature… 16ºC
-

straight 25ºC
-

curly



Himalayan rabbit… below 33ºC black in color… above… white



Oncogenes…..cancer



Green plants…. Size…shape….fullness


MUTATIONS

2 types



inherited




non
-

inherited



-

sex cell




-

body cell

1.
Chromosomal alterations:
-

seen phenotypically

Examples:





-

non
-
disjunction






-

polyploidy
-

more than one set of chromos




common in plants causing them to appear fuller,




vigorous, sterile (produce plants w/o seeds) ex.




potatoes, apples, watermelon, wheats






-

changes in chromo structure
-

breaking off or



attachment to another chromo





a
-

translocation: movement of part of a chromo





to a non
-

homologous chromo





b
-

Addition/ Deletion
-

parts are added or lost





C
-

Inversion
-

when the reading is upside down or





inverted






d
-

Duplication/ deletion
-

when a base is repeated or



completely
not included


2
-

Gene Mutation:



-

change in the chemical structure
-

some noticeable and



some are not ex. Albinism



-

most are recessive because you are not generally



homozygous
for a mutation



-

obviously not generally advantageous… most are lethal

Examples:


-

Point mutation
: affects one nucleotide, usually one is substituted


for another


-

Frame Shift
: occurs when there is an addition or deletion of a nucleotide
-


this totally shifts the
transcription of mRNA which in turn GREATLY affects the

function of the protein


3. Mutagenic Agents:


a. radiation


b. chemicals( medications, exposure on the job…..)


Detection of Genetic Defects:


1. Amniocentesis


2. Karyotyping
-

enlarged photo of homologous chromos


3. Screening
-

body fluids( sweat, urine….) detect presence or lack of certain enzymes


HOW DO WE GET AND KEEP DESIRED TRAITS???


1. Artificial Selection: mating individuals with desired traits


2. Inbreeding: breeding organisms with very similar genetic material/ or mating

organisms that have been
selectively breed


3. Hybridization: 2 species… 2 traits…. Hybrid population


4. Preservation: mutant recessive
–

vegetative propagation…grafting

Genetic engineering is when humans control breeding outcomes by either controlling DNA or the organisms that breed.



examples include:



selective breeding



In breeding



Induced mutations ( by radiation or chemicals)




-

this has proven successful with Bacteria ex. Oil digesters




-

successful with plants ex. Certain drugs prevent the



separation of chromos during meiosis( polyploidy)..








Strawberries

CONTROL OF DNA:


-

extracting


-

cutting/ splicing
-

requires the use of restriction enzymes…. The new DNA made

is called recombinant
DNA


-

separating…. Gel electrophoresis

TRANSFORMATION:


-

DNA outside the cell is taken in and it incorporates itself in the DNA within the

cell



-

bacteria
-

DNA molecule is called a plasmid…. If we incorporate a specific

piece of DNA into a
bacterial plasmid we can use them to help us make proteins


ex. Insulin…. Interferon


APPLICATIONS OF GENETIC ENGINEERING


-

Transgenic animals and plants( genetically modified)



… extra growth hormone…. Built in pesticides…..plants who make



human abs…golden rice…

CLONING:


-

involves the removal the nucleus from an egg cell and the insertion( generally) of


a somatic cell nucleus into that egg and then implantation of the cell into the uterus


of the “mother”



ex. DOLLY














Types of cloning include:


-

reproductive


-

theraputic


-

DNA


LAST, but NOT LEAST Population Genetics

Population genetics is the study of genetic characteristics of a species and of the factors that affect frequencies of genes
in
the
population.


A. Population
-

all members of a species in a given geographical location at a given time.




Ex. All the whitetail deer living in a mountain valley or all the dandelions


inhabiting a vacant lot


B. Gene Pool
-

sum total of all the inheritable traits in a given population


C. Gene Frequency
-

% of each allele for a particular trait in a population. Possible to




predict by applying simple statistical formulas to experimental data.




Ex. 60% of genes controlling ability to taste PTC paper are recessive, 40%




are dominant






Celebrity Sheep Died at Age 6


Dolly, the first mammal to be cloned from adult DNA, was put down by
lethal injection Feb. 14, 2003. Prior to her death, Dolly had been suffering
from lung cancer and crippling arthritis. Although most Finn Dorset sheep
live to be 11 to 12 years of age, postmortem examination of Dolly seemed to
indicate that, other than her cancer and arthritis, she appeared to be quite
normal. The unnamed sheep from which Dolly was cloned had died several
years prior to her creation. Dolly was a mother to six lambs, bred the old
-
fashioned way.

** also possible to predict proportion of a population that is homozygous and heterozygous


HARDY
-
WEINBURG PRINCIPLE:


-
the gene pool( gene frequencies) of a population should remain stable over many generations as long as
certain conditions are met.


1
-

ideal conditions include….large pop…sexes represented equally…random

mating…no migration in or

out…no mutations of genes or chromos occurs

** these conditions are rarely met in reality so therefore genetic stability cannot normally occur. Gene pools are instead in

a
steady state of dynamic change. This along with variation caused by genetic mechanisms is the driving force behind
evolution.






p2 + 2pq + q2 = 1
and

p + q = 1

p = frequency of the dominant allele in the population

q = frequency of the recessive allele in the population

p2 = percentage of homozygous dominant individuals

q2 = percentage of homozygous recessive individuals

2pq = percentage of heterozygous individuals



QOD: Decode the following message:

9 12, 15, 22, 5 7, 5, 14, 5, 20, 9, 3, 19




TRANSLATION….TRANSCRIPTION….REPLICATION

Hydrogen
bonds

Nucleotide

Sugar
-
phosphate
backbone

Key

Adenine (A)

Thymine (T)

Cytosine (C)

Guanine (G)

DNA Structure

Growth

Growth

Replication fork

DNA polymerase

New strand

Original strand

DNA polymerase

Nitrogenous
bases

Replication fork

Original strand

New strand

DNA

Replication







DNA strand is opened by restriction enzymes…..mRNA reads the open
segment( translation) A
—
U G
---
C….mRNA than leaves the nucleus and
enters the cytoplasm in search of rRNA….once rRNA is found the single
strand of mRNA attaches to rRNA…..tRNA now enters the picture
(transcription)… tRNA reads each codon ( 3 bases)… a codon codes for
a specific amino acid..(replication) the AA are put in order to form a
specific polypeptide( a codon chart is used to assist in interpreting the
codons….

RNA

DNA

RNA

polymerase


Transcription

Adenine (DNA and RNA)

Cystosine (DNA and RNA)

Guanine(DNA and RNA)

Thymine (DNA only)

Uracil (RNA only)

Messenger RNA

Messenger RNA is transcribed in the nucleus.

Transfer RNA

The mRNA then enters the cytoplasm and
attaches to a ribosome. Translation begins
at AUG, the start codon. Each transfer
RNA has an anticodon whose bases are
complementary to a codon on the mRNA
strand. The ribosome positions the start
codon to attract its anticodon, which is part
of the tRNA that binds methionine. The
ribosome also binds the next codon and
its anticodon.

mRNA

Start codon

Ribosome

Methionine

Phenylalanine

tRNA

Lysine

Nucleus

Translation

mRNA


The Genetic Code

Transcribe and Translate a
Gene