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Showing posts with label genetics. Show all posts
Showing posts with label genetics. Show all posts

Tuesday, September 4, 2012

Why Life Begins at Conception, Part 4


The sperm (from the father) and the egg (from the mother) each carry one half of the parent’s genetic information.  At fertilization, a full set of genetic information is present; the exact same full set of information which is present in every cell of the adult individual.  Between thirty and one hundred fifty million sperm compete to reach an egg after each sexual act.  Each one of these sperm carries one half of the full set of the father’s genetic information.


The fertilized egg begins almost immediately to reproduce itself. Each copy carries a  full set of genetic information; the exact same full set of information which is present in every cell of the adult individual.


The cells form a flattened disk called the blastodisc and a groove, the neural groove, develops in the middle of the disk.  The walls of the groove rise up and close together to form the neural tube.  The neural tube becomes the spinal cord.  Each cell in the structure carries a  full set of genetic information; the exact same full set of information which is present in every cell of the adult individual.

This short video is of a chicken embryo, but the process is exactly the same in the human embryo.


At each step of the baby’s development every cell in the body carries a full set of genetic information; the exact same full set of information which is present in every cell of the adult individual.   If a blind DNA analysis were to be performed on two separately submitted specimens, on the embryo and on tissue taken from the mother, the result would be this: the analysis would show two individuals who were related genetically.  

Tuesday, August 28, 2012

Why Life Begins at Conception, Part 3

(The posts in this series may not occur on consecutive days but they will make the most sense to you if they are read in consecutive order.)

This is a very simplified presentation of human conception and the passage of genetic information from the parents to the offspring.  (An aside: how can any rational, normally intelligent person see this level of complexity and order and still deny at least the possibility of an intelligent designer?)

The information may seem to be complicated and overwhelming, but at least a simplified basic
understanding is necessary for a scientific attack on abortion.  That is what I will attempt to provide for you here.  It is necessary to start at the beginning, DNA (deoxy-ribonucleic acid).

DNA is a spiral molecule consisting of two strands paired together in the shape of a helix.  DNA is present in every cell of the human body and, in every one of those cells, the DNA contains ALL the information necessary to build and maintain the entire body.

DNA is a very complex and a very simple molecule.  It basically is two strands joined by matched pairs of bases.  Only four bases (adenine, guanine, cytosine, and thymine) are used.  Combinations of these four bases contain the entire genome; the genetic code which determines a person's hair color, voice, skin color, height, body type, number of fingers and toes, intelligence level, athletic ability, etcetera, etcetera, etcetera. The code determines everything about your physical body.  Literally everything, and genetic science says that all that information about you as an individual is present from the moment of conception.

A very simplified explanation is this.  In the sperm and egg cells, each cell receives one strand of the two DNA strands.  At fertilization, the two strands join to form one complete strand.  So, half of the information comes from the mother and half from the father.  The fertilized egg then is a hybrid of the two source cells, made from them but entirely different from them;  a fully separate genetic code, a separate individual.

More in the next post.
.....................................
If you wish to know more, see these links.

Very good:
Simplified:
DNA to RNA to proteins
Detailed information on proteins:
Chromosomes

Monday, June 6, 2011

Film Comment: Splice

"She's not human ... not entirely."  This is the tagline for the truly disturbing 2009 Canadian science fiction film, Splice , starring Academy Award winner (2002) Adrien Brody, Canadian actress Sarah Polley, and French actress Delphine Chaneac in the role as the adult creature/specimen/thing/woman.  When I saw this film , I heard someone say that they felt like they needed a bath upon leaving the theater. It is that intense, bizarre, and perverse.

A male-female genetic research team (Brody and Polley) at the Nucleic Exchange Research and Development laboratory (N.E.R.D.) are working on creating hybrid animals (mixing genetic material from several species) for medical use.  When their funding is threatened they rush to accelerate their results and secretly add human DNA (their own) to the mix.  A viable little bird-like thing results.  They name it Dren (N.E.R.D. spelled backwards) because the female researcher almost immediately takes a mothering attitude toward the creature and insists that it is not a "specimen."

Dren cannot speak, after all, she is an animal; she coos like a bird.  She proves to be inquisitive, intelligent, graceful, and she grows at an alarming rate.  She is an adult within days.  She is tall and slender with a beautifully innocent face, her knees bend backward instead of forward, her feet resemble hands, and she has a long prehensile tail tipped with a poisonous stinger.

As she matures, Dren becomes very noticeably female and increasingly seductive. "Poppa" makes the mistake of spending time alone with her and willingly/unwillingly ends up as the object of her intense attention.  Then his wife catches them.  He is having sex with his "daughter," he is having sex with an animal, he is having sex with himself.  Dren is all three.

This film touches on the subjects of cloning, responsibility toward our offspring, aberrant sexuality, intense self pride, and amoral scientific research just for the "science."  It is, in reality, a variant on the Frankenstein theme.

The most disturbing thing about this film is that it is on the edge of no longer being science fiction.  Much of science fiction eventually becomes science fact.  Jules Verne wrote of space travel and submarines; now they are established fact.  On the first Star Trek television series, the characters would reach into their pockets and pull out their personal communicators; we now call them cell phones.

Modern molecular biology can already insert DNA sequences into bacteria and cause them to produce synthetic chemicals they would normally not produce.  The entire human genome has now been deciphered with the prospect of the ability to insert healthy DNA sequences in place of faulty ones.  The mutant genetic sequence which causes the bacterium Staphylococcus aureus to be resistant to methicillin (MRSA) can be detected in one hour from a nasal swab.

Artificial life may be just around the corner.  It may already be here.  In 2010, Dr. John Craig Venter of Utah, USA announced the creation of an artificial bacterium using synthetic DNA.  His research is aimed at producing modified microorganisms which can produce clean fuels and biochemicals.

Christians believe that God is the Creator.  There are so many questions. What will it mean if man also is a creator?  What will God think of our glorification of the human intellect?  Does God intend for us to learn all things?   Are there things we should not learn?  Are there things we should not do even if they are possible? Do scientists bear any responsibility for their discoveries?  What if our science creates a Dren?

Friday, July 31, 2009

DNA explained for the layman

     Human reproduction is based on the incredibly complex chemical compound known as DNA (deoxyribonucleic acid), which carries all of the genetic assembly, maintenance, and functional information for the human body, different and distinct for each individual human body, with the entire code present in every cell of the human body (except of course, the reproductive cells, which carry one-half of the genetic information.)
     The genetic information carried in DNA is coded using a sequence of four bases (adenine, guanine, cytosine, and thymine) arranged in pairs on opposing helical strands with molecular weights in the millions.  The number and sequence of base pairs enables millions of instruction to be encoded in each DNA strand.  This structure is simple and complex at the same time and its elucidation won the 1962 Nobel Prize in physiology and medicine for James D. Watson and Francis Crick.
   Strand-like paired structures (twenty three pairs of chromosomes in normal humans) found in human body cells each carry millions of coded instructions on the DNA strands of which they are constructed.  The chromosomes are duplicated when new cells are produced so that each new cell carries the same set of instructions as all others.  The two exceptions are the reproductive cells (spermatozoa and ova), which, instead of being diploid (two stranded) have only one DNA strand (haploid).   When the sperm fertilizes the egg (ovum) the individual (haploid) strands of DNA are united, producing an entirely new diploid individual related to,  but distinct from, the two source cells.  The new life can literally be said to be half from the mother and half from the father.

  

Wednesday, July 29, 2009

The abortion debate is not only based on religious beliefs

     A friend and I were talking  and somehow got onto the subject of abortion.  When I expressed my opposition to the practice he told me he was surprised at me.    He said, "You're so well read and seem to be intelligent.  How can you be anti-choice?"
     I pointed out to him that I am not anti-choice, I'm pro-life.  He started rolling out all the pro-abortion arguments.  And, he made the charge that only fundamentalist Christians and Roman Catholics oppose abortion; so, declaring that it was not necessary to invoke religion at all in the debate, I asked him a question.
     "If you take tissue from an aborted fetus and from the biological mother and submit the samples separately for DNA analysis and comparison, what will be the result?  ... The DNA analysis will demonstrate that the tissues came from two separate and totally distinct individuals.  Genetic science states that the fetus, from the moment of conception, is a separate life, not merely a patch of tissue in the mother's body."
     My friend admitted that this was true but the implications of that admission flew right over his head.  He resorted to the hypothetical game, "If your daughter were ... "
     Many people of both liberal and conservative orientations stake a claim on a particular issue on ideology and become almost automatons, chanting the established mantra over and over.  They challenge any deviation from their particular orthodoxy.  Real argument, in the classical sense, is drowned out; they merely become louder with their chanting.  If you don't agree with them you must be an uneducated boob, hopelessly confused, or, worst of all, a bigot.
     It would be a positive step if we could all learn to argue with respect.  At the end of our argument my friend and I looked at one another and laughed.  We're still friends.