final - genbio2

• genetic inheritance

  is the passing of traits from parents to their offspring.Genetic inheritance is the passing of traits from parents to their offspring.
• genotype

  refers to the two alleles an organism has inherited for a particular gene. Alleles can be recessive or dominant
• phenotype

  is a result of the expression of one or more genes. could be: Brown hair, AB blood type or blue eye color
• dominant

  only one allele is needed for the trait to be expressed
• recessive

  two alleles are needed for the trait to be expressed
• Gregor Mendel

  •Once upon a time (1860's), in an Austrian monastery, there lived a monk named Gregor Mendel.

  • Mendel spent his spare time breeding pea plants.

  •He did this over & over & over again, and noticed patterns to the inheritance of traits, from one set of pea plants to the next.

  •By carefully analyzing his pea plant numbers, he discovered three laws of inheritance
• law of segregation

  • During gametes formation, every paired alleles separate (segregates) randomly so that each gamete receives one allele or the other.
  • The two alleles of a gene present in the F1 do not mix with each other; they separate and pass into different types of gametes in equal proportion.
  • The pair of alleles of each parent separate and only one allele passes from each parent on to an offspring.
  • Which allele in a parent’s pair of alleles is inherited is a matter of chance.
• law of dominance

  • Every gene has two alleles for a trait.
  • One allele is dominant and will always express.
  • One allele is recessive and it will be suppressed by the presence of the dominant allele.
• law of independent assortment

  • This law states that allele pairs separate independently during the formation of gametes.
  • This means that traits are transmitted to offspring independently of one another
• classical breeding

  • practices focus on the mating of organisms with desirable qualities
• genetic engineering

  • a process of making changes on the genetic code of an organism
  • its goal is to add one or more new traits that are not normally found in that organism
  • scientists have been able to employ different techniques to extract, cut and make unlimited copies of DNA
• genetic engineering

  • it involves the use of molecular techniques to modify the traits of a target organisms

  1. introduction of new traits into an organism
  2. enhancement of a present trait by increasing the expression of the desired gene
  3. enhancement of a present trait by disrupting the inhibition of the desired gene's expression
• DNA recombination

  • is a process of modifying the genes of organisms for practical purposes
• recombinant DNA

  • it is done when a piece of DNA is combined with another DNA from another source
• processes used in recombinant DNA technology

  1. transformation
  2. vectorless gene transfer
  3. transduction
• transformation using a vector

  • recombinant DNA may be created through transformation with the help of a vector, such as bacterial cells.
• transformation using a vector

  • vectors are organisms that are normally harmless but may help spread infection by transferring the genetic material from one host to another
  • in the transformation process, a selected portion of the foreign DNA is inserted into a small, circular DNA molecule called plasmid, which is naturally found in bacteria
• transformation using a vector

  • plasmid are most useful tool in gene transformation for two reason

  1. plasmid contains a gene sequence that serve as bacterial origin of replication
  2. it also contains a genetic marker, which makes it possible to distinguish bacteria that carry the plasmid-containing foreign DNA
• transformation using a vector

  • during transformation, a restriction endonuclease enzyme is used to cut the piece of the donor DNA. this enzyme cleaves the DNA at the phosphate-sugar bond.
  • stick ends are areas in the DNA where the bases are ready to be paired
• transformation using a vector

  • restriction enzymes cut the DNA only at a specific nucleotide sequence. they work precisely like a key that fits only one specific lock.
  • DNA ligase is a enzyme used to insert the donor DNA into the vector
• transformation using a vector

  • The recombinant DNA is then inserted into a bacterial cell, such as E. coli
  • After transformation, the culture is treated with an antibiotic. Those that have been transformed will be the only ones to survive because they carry the resistance gene.
• vectorless gene transfer

  • This process is similar to transformation, but it does not involve vectors. The types of vectorless gene transfer include electroporation, protoplast fusion, microinjection, and use of a particle gun.
• vectorless gene transfer

  1. electroporation

  temporary holes are formed in the plasma membrane of the host cell by applying a significant amount of electricity in the culture medium. This enables the entry of foreign DNA via the pores.
• vectorless gene transfer

  2. protoplast fusion

  cells are treated with chemicals to initiate recombination. In this process, bacterial cell walls are digested, turning the cells into protoplasts.
• vectorless gene transfer

  3. microinjection

  the host cell is immobilized by applying a mild suction with a blunt pipette. The foreign gene is then injected with a microinjection needle, thus creating recombinant DNA.
• vectorless gene transfer

  4. particle gun

  the host cell is bombarded with tungsten particles coated with foreign DNA. This process is used in the field of agriculture.
• transduction

  • is the process wherein genetically engineered bacteriophages- viruses that parasitize bacteria- are introduced into the cell to create the desired recombinant DNA.
• American researcher Steven Howell and his associates at the University of California in San Diego learned that even genes from two or more different organisms can be made to work together.
• Howell’s team tried to isolate the gene for luciferase- an enzyme that allows fireflies to glow- and insert it into tobacco cells. When the gene was activated from the recombinant cells, the plants glowed in the dark. This means that the basic mechanisms of gene expression are shared by both plants and animals.
• Agriculture

  • Transgenic plants, or plants that contain genes from other organisms, are now an important part in the field of agriculture.
  • By using recombinant DNA technology, plants can now be grown with genes responsible for producing natural insecticides.
  • This technology reduces the need for synthetic or artificial insecticides and pesticides.
• Bacillus thuringiensis bacterium

  • In the Philippines, recent developments have enabled plants to express a recombinant form of protein used.
• other applications of recombinant DNA to agriculture are

  1. crop improvement
  2. genetically engineered traits: the big six

  • herbicide resistance
  • insect resistance
  • virus resistance
  • altered oil content
  • delayed fruit ripening
  • pollen control

  3. biotech revolution

  • cold and drought tolerance and weather- guard genes
• medicine

  • An important contribution of recombinant DNA technology in the field of medicine is the use of bacteria to create substances that our body needs whether to maintain good health or to treat a disease
• other medical applications of recombinant DNA technology

  1. production of proteins for replacement therapy(e.g. insulin), disease prevention(e.g. vaccines) and diagnostic tests(e.g. monoclonal antibodies)
  2. treatment of genetic diseases( gene therapy)
• food industry

  • Recombinant technology has also improved the food industry. Some of the crops that we eat are now resistant to pests, diseases, and environmental stress. As a result, crop yields have increased and production costs have been kept lowered.
  • Recombinant crops are also beneficial because of their improved nutritional quality and longer shelf life.