Skip to main content

CRIME AND DNA

 

    

      Every cell in the body holds DNA (deoxy ribonucleic acid), a complex molecule made up of smaller molecules called nucleotides.  There are four types of nucleotide 1. cystonine (c) 2. guanine(g) 3. adenine(A) 4. Thymine(T).  DNA is arranged into structures called chromosomes.  They make up human genome.  The full genome holds 6.5 million characters made up of C, G, A, and T, while a 300-page book has 300000 characters made up of 26 alphabets.  Human Genome project transcribed all the nucleotides (characters).  It took two decades.  More than 90 % of our DNA is like Monkey's DNA.  Our characteristics such as hair color, eye color, height and other physical features are coded in the 2% of our DNA.  The purpose of remaining 98% of the DNA is just being identified. 

    In certain regions of our DNA, there are unique repeating patterns that can be used to differentiate one person from another.  There patterns are known as short-tandem-repeats-STR. 
Example: TACATACATACATACATACA 
Here TACA repeats. 
     Some regions of DNA may have 10 STR, other regions may have 13.  Finally, 'the number of STR in each region is our ID".  No two persons have same number of STR in all the regions.  But, two persons may have same number of STR in just one location.  Even that has a chance of one in ten million. 
     Blood cells, sweat, body-fluids, skin-cells left behind at the crime scene can be examined for their unique 'STR signature" to link a person to the sample.  Hence fool (full) -proof crime is impossible. 

 
FOOT NOTE:  

'Twins may have same STR signature'.  Besides DNA evidence other evidences strengthen and strengthen the criminal case.        

 The nature, plant and animals build themselves using DNA blueprint.  Even banana's DNA and ours are mostly same.  Today, we know that information and coding is key.  Hence nature's key also DNA coding.  Even virus have DNA coding.  Tomorrows medicine will be based on DNA. 


Labels:

Comments

Post a Comment

Popular posts from this blog

LISSAJOUS FIGURES

  Definition:  "When a particle is subjected to two sine wave motion or two oscillatory motion at right angles, the particle describes lissajous figures".      We know sine wave motion and circular motion is basically same.  Hence we draw two circles A and B perpendicular to each other.  The circle B rotates twice faster than circle A.  That is, frequency of circle B is two times than that of A.        A particle at the intersection of two circles is subjected to two sine wave motion   A and B at 90 degree simultaneously.  The particle will describe figures depending on the frequency and phase of A and B .  In our case, the ratio of frequency is  1:2 and the two waves are in phase.        To draw lissajous figures :  A moving point in both the circles are chosen.   Here we should remember; during the time taken by the circle A to complete one rotation, circle B completes two.  Hence the points are marked on the circles according to their speed.  Then straight lines
Post a Comment
Read more

THE PARABOLA

          A jet of water shooting from a hose pipe will follow a parabolic path.  What is the so special about parabola.    Y= x^2 Draw a graph for the above equation.  It will result in a parabola.  This parabola is also called unit parabola.  Any equation involving square will yield a parabola. Example:  Y = 2x^2 +3x+3 (also called quadratic equation)    X= 2 and -2, both  satisfies the equation 4 = X^2.  Parabolic equations always have two solutions.     Any motion taking place freely under gravity follows parabolic path. Examples:   An object dropped from a moving train,   A bomb dropped from flying plane,  A ball kicked upwards.      If a beam of light rays fall on the parabolic shaped mirror, they will be reflected and brought to focus on a point.  This fact is made use of in Dish Antenna, Telescope mirrors, etc.      Inverted parabola shape is used in the construction of buildings and bridges.  Because the shape is able to bear more weight.      A plane
Post a Comment
Read more

CASINO'S GAME

           Let us find out how the casino survives with mathematics.      Say, your friend invite you for a game of dice.  You must bet (wager) 2 dollars.  If you roll 'six' you will get back 8 dollars.  The game will go on for 30 rounds.  All sounds good.      The probability of rolling 'six' is 1/6.  Since the game will be played for 30 times, the 'expected win' is 30*1/6 = 5.  That is, you are expected to win 5 rounds out of 30.  Hence your gain will be 5 * 8 =40 dollars.  ok.  This also implies that you will loose 25 rounds.  Hence your loss will be 25*2 =50 dollars.  Your net gain will be gain-less = 40-50 = -10 dollars. For 30 rounds, the loss is -10 dollars, Hence, for one round =-10/30 = -1/3 dollars.  There will be a loss of -1/3 or 0.33 dollars per round.  It is not a fair game.     Let us make a simple formula to calculate  'Pay out per round\. The probability for a win = p The pay-out in case of win = V No. of rounds = n The expect
4 comments
Read more