recombinant DNA technology

recombinant DNA technology
What is recombinant DNA?
Recombinant DNA is the formation of a novel DNA sequence by the formation of two DNA strands. These are taken from two different organisms. These recombinant DNA molecules can be made with recombinant DNA technology.
Wat is recombinant DNA technology?
The procedure is to cut the DNA of the donor organism into pieces with restriction enzymes, and insert one of these fragments into the DNA of the host. Most of the time a bacterial or virus plasmidis used to insert the donor DNA. A plasmid is a circular DNA fragment, which can be opened with the same restriction enzymes as the DNA fragment of the donor. A plasmid containing DNA from the donor is called a vector. The recombinant vector can then be used to transform bacterial or virus cells. These bacterial cells are plated and colonies are grown.
Antibiotic resistance
To only get the recombinant DNA containing bacteria, an antibiotic resistanceis built in the vector. The bacteria are then put on an anitbiotic containing plate. This means that only the vector containing bacteria will survive, because only they contain the antibiotic resistant gene.These grown colonies all contain the same recombinant vector in their genome. These population with all identical DNA inserts is called a DNA clone. When an entire genome is cut and grown in different colonies, you have a DNA library.
Recombinant eukaryotes
Dependant on the kind of bacteria you use, different experiments with the altered vectors are possible. First of all, it is possible to sequencethe inserted gene. In this way you can get the DNA sequence of a whole or a part of te genome. Another option is to use a bacterium which can infect other organismslike plants, animals or fungi. One of the examples of making recombinant plants, is the use of a bacterium called Agrobacterium tumefaciens. This bacterium can insert the vector, which contains the recombinant DNA, into a plant. In this way, a recombinant plant is made which can make the gene products of the inserted recombinant genes.
In the techniques written above all organisms and enzymes that are used come from nature themselve. All steps occur in nature themselve very regular. Only the insertation of eukaryotic genes into the plasmid of a bacteria is not seen yet in nature. But researchers expect that this is also a process which occurs in nature itself.

Sex influenced and Sex limited inheritance

sex-influenced inheritance
Inheritance that is autosomal but has a different intensity of expression in the two sexes, as that manifested in male pattern baldness. Dominant in any on .
..autosomal chromosome rrespnsible

sex-limited inheritance
Inheritance in which a trait or phenotype is expressed in one sex only, as in hemophilia A
Autosomal chromosomes responceble
Darhi in male...

Sex linked Inheritance

Colour blindness. A particular traits in human beings renders them unable to differentiate between red colour and green colour. The gene for this red green colour blindness is located on X-chromosome. Colour blindness is recessive to normal vision so that if colour blind man marries a girl who is normal (homozygous) for this character, sons will be normal, but daughters will be heterozygous (normal phenotype), which means that these daughters would be carriers of this trait. If such a carrier girl marries a colour blind man, 50% of female progeny and 50% of male progeny would be colour blind (Fig. 16.9).
Hemophilia. Hemophilia is another popular example of sex linked inheritance in human beings. It is recessive character and is, therefore, masked in heterozygous condition. Individuals suffering with this disease lack a factor responsible for clotting of blood. Consequently, even a minor cut may cause prolonged bleeding leading to death. Since it is a recessive character, a lady may carry the disease and would transmit the disease to 50% of her sons, even if the father is normal (Fig. 16.10).

Fundamental principal of genetics

Fundamental Principles of Genetics
(Biol/ MbioS 301, Spring 2003)
The following observations are listed roughly in the chronological order in which they were made. It should be helpful for you to track where we are in the course according to these principles and to try to understand the evidence for each. In a few cases, there are exceptions to these principles and it would be advisable to be aware of those.
Genes are inherited according to simple rules.
Genes are located on chromosomes.
Genes on the same chromosome tend to be passed on together.
Microorganisms, including bacteria and their viruses, can be convenient organisms for genetic research.
Genes direct the formation of enzymes.
DNA is the genetic material.
DNA is structured as a double helix.
DNA -----> RNA -------> protein
The expression of genes can be regulated by the binding of proteins to DNA.
Eukaryotes have greater genomic complexity than do prokaryotes (e.g., repeated DNA, introns, genome size).
The ability to analyze and manipulate genes has progressed dramatically.
Mutations in developmental control genes can provide insights into the process.
Allele frequencies and genotype frequencies are related, and can change in response to several factors.
Many important traits show complex inheritance, and the genetic influences on such traits can be analyzed both statistically and functionally.