Inversions- DNA segment is excised and reinserted in opposite orientation.
*Codon-a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis.
Insertions are mutations in which extra base pairs are inserted into a new place in the DNA.
Deletions are mutations in which a section of DNA is lost, or deleted.
In an inversion mutation, an entire section of DNA is reversed.
The fat cat ate the wee rat.
The fat tar eew eht eta tac.
Typically affect a larger amount of genetic information than gene mutations.
Mutations make an important contribution to variation of traits.(evolution)
Mutations may be harmful, beneficial, or neutral...
-Proteins that are made from the genetic code are non or less funtional.
-Proteins that are made have more function or a new function that's beneficial.
A mutation isn't beneficial or harmful.
-refers to a procedure that is performed under sterile conditions.
, a mutation in the Kit protein:A separate mutation, called (Ws) knocksout the , a tyrosine kinase transmembrane receptor,which is produced by the c-kit gene. The mutation is a 12-basedeletion in the c-kit gene (Tsujimura 1991). The kitprotein has a wide variety of functions! Kit is involved in thedevelopment of blood stem cells (precursors to red and white bloodcells), melanoblasts, and primordial germ cells, and melanoblastmigration (Horie 1991). So knocking out the kit proteinwill have a variety of effects, including: depigmentation of certainareas (up to and including entirely white with black eyes), andsometimes anemia, a deficiency of mast cells (and thereforedeficiencies in histamine and serotonin), reproductive problems anddeafness (Kitamura 1994, Hoshino 2000, Sugimoto1995).
Rats come in a side variety of colors and patterns, from solidblack to white, from dark browns to warm tans to creams, from slategrey to pale blue. Rats can display patches of white that range froma small chest spot to a belly blotch to white with a pigmented headand beyond. The variation is immense! Where do these coat colors andpatterns come from? How are the different pigments made andintegrated into the growing fur? How do mutations along the pigmentproduction pathway produce the different colors we see in rats?
These relationships are often called the rules of Watson-Crick base pairing, named after the two scientists who discovered their structural basis.
Code for various traits or features in an organism by coding for proteins that have specific functions.
LaFreda J Howard
October 8, 2014
Lab 5: DNA , Protein Synthesis, and Genetic Mutation
RNA-ribonucleic acid, a nucleic acid present in all living cells.
The diagram above shows the difference in the synthesis of in normal DNA and abnormal DNA. The top strand shows the normal DNA, mRNA and amino acid sequences. A single substitution mutation has changed the base sequence in the DNA. The base sequence on the mRNA produced by the DNA is altered. As a result, a codon on the mRNA is altered. A different amino acid is inserted into the protein chain. The amino acid valine is inserted instead of glutamic acid, which is shown by the bottom strand of DNA. The protein is altered and no longer functions normally. These sequences result in sickle-shaped red blood cells. This blood disorder is known as sickle cell anaemia.
Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses RNA rather than DNA carries the genetic information.
The rules of base pairing (or nucleotide pairing) are:
A with T: the purine adenine (A) always pairs with the pyrimidine thymine (T)
C with G: the pyrimidine cytosine (C) always pairs with the purine guanine (G)
The purine adnenine (A) will pair with the pyrimidine uracil (U) instead of thymine (T)
Base pairing is achieved by hydrogen bonds, a type of noncovalent reaction.
Why not A with C and G with T?
In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes.
This shows the normal order of the bases for one of the strands in the area highlighted in the DNA molecule. Only one of the strands of DNA is involved in protein synthesis. A change from the normal order of bases leads to different types of gene mutation.
These aren't the only roles of the Kit protein, however. Kit isalso used in intestinal contractions: Special cells in the intestinewall, called intersticial cells of Cajal (ICC) generate electricalslow waves in the gastrointestinal tract. These slow waves regulatethe frequency of intestinal muscle contractions, so ICC are criticalfor normal motility of the small intestine. ICC synthesize Kit, theproduct of c-kit. Rats with the white spotting mutation don't produceKit in their intestines, and don't show electrical slow waves. Thisresults in abnormal contraction and megacolon (Takeda et al.2001).
In humans, mutations in the MCR1 receptors cause melanocytes tosynthesize red-yellow phaeomelanin, which produces red hair. Thereare 6 known mutations in MCR1 which vary in how much they knock outMCR1's function. Red-haired individuals are usually homozygotes orcompound heterozygoes (posessing two different types of MCR1mutation). Two alleles for non-functional MCR1 will produce brightred hair. People with just one mutated MCR1 allele, or alleles thatonly partly impair MCR1's function, may show varying shades of red,or no red at all. About 50% of white people carry a mutated MCR1,which is thought to be significantly associated with fair skin evenif it does not produce red hair (Ha and Rees 2001, Rees 2000,Schaffer and Bologna 2001).
Once the pigments are made, they have to be transported to thehair. The pigment particles, called granules, are synthesized inlittle vesicles called melanosomes, which are transported via thedendrites of the melanocyte to the shaft of the growing hair. Thetransport is actually really neat... melanosomes are carried bylittle molecular feet (myosin 5, an actin dependent motor protein)along little branching molecular "ladders" (actin filaments)contained in projections off the melanocyte (dendrites) to the cell'sedge. If this transportation system is affected, transport to thecell edge isn't normal.