More Genetic Mumbo-Jumbo
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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

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More Genetic Mumbo-Jumbo

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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


2 types

inheritednon- inherited

- sex cell- body cell

  • 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


- 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

Genetic Engineering

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


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


- extracting

- 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


- 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:

- reproductive

- theraputic


  • 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

** 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 



DNA Structure


Hydrogen bonds

Sugar-phosphate backbone


Adenine (A)

Thymine (T)

Cytosine (C)

Guanine (G)

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


New strand

Original strand

DNA polymerase


DNA polymerase


Replication fork

Replication fork

Nitrogenous bases

New strand

Original strand

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

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.




Start codon

The Genetic Code

Transcribe and Translate a Gene

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