More 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
More 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
Green plants…. Size…shape….fullness
- sex cell- body cell
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
- 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:
b. chemicals( medications, exposure on the job…..)
Detection of Genetic Defects:
2. Karyotyping- enlarged photo of homologous chromos
3. Screening- body fluids( sweat, urine….) detect presence or lack of certain enzymes
Genetic engineering is when humans control breeding outcomes by either controlling DNA or the organisms that breed.
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
5. 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:
- cutting/ splicing- requires the use of restriction enzymes…. The new DNA made is called recombinant DNA
- separating…. Gel electrophoresis
- 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…
- 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”
Celebrity Sheep Died at Age 6Dolly, 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.
Types of cloning include:
** also possible to predict proportion of a population that is homozygous and heterozygous
-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 populationq = frequency of the recessive allele in the populationp2 = percentage of homozygous dominant individualsq2 = percentage of homozygous recessive individuals2pq = percentage of heterozygous individuals
QOD: Decode the following message:
9 12, 15, 22, 5 7, 5, 14, 5, 20, 9, 3, 19
The average human chromosome contains 150 x 106 nucleotide
When DNA replicates prior to cell division:
Before a cell divides, its DNA is replicated (duplicated.) Because the two strands of a DNA molecule have complementary base pairs, the nucleotide sequence of each strand automatically supplies the information needed to produce its partner. If the two strands of a DNA molecule are separated, each can be used as a pattern or template to produce a complementary strand. Each template and its new complement together then form a new DNA double helix, identical to the original
DNA strand is opened by restriction enzymes…..mRNA reads the open segment( transcription) 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 (translation)… tRNA reads each codon ( 3 bases)… a codon codes for a specific amino acid..(replication/ formation of a polypeptide) the AA are put in order to form a specific polypeptide( a codon chart is used to assist in interpreting the codons….
Summary of the WHOLE Process
Adenine (DNA and RNA)
Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
Messenger RNA is transcribed in the nucleus.
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.