|
|
DNA Simply an abbreviation for DeoxyriboNucleic Acid. But what it does is hard to grasp for most of us. It has been referred to as the blueprint or encyclopedia of life.
What's it made up of ? Well if we use the analogy of the encyclopedia
then what's inside the DNA encyclopedia ? Every living thing is different
but many are similar too. With the exception of identical twins and
now clones this is true.
Even if you inbreed forever there would still be differences.
Every cell in every living thing has two sets DNA as well except for sperm and eggs which have but one set each. Why, because when they "get together" they will have two, together (fertilization).
This DNA encyclopedia is quite similar to books, in that, the whole thing is made up of simple words or instructions the difference is these words are chemicals and not ink. These chemicals are called nucleotides. They form the "words" and "books" they are not called words and books however they are called "condons" and "genes".
Now while we are used to using 26 letters in our alphabet other
languages do not have the same number of letters neither does DNA's code
language. It in fact uses only four letters. What are they called? (A)
Adenine, (T) Thymine, (G) Guanine and (C) Cytosine. Doesn't seem like many
letters does it? Well let's assume for the sake of this
explanation that we have a "word" 4 letters long how many different
4 letter words can
we make with a 4 letter alphabet? Well, 4x4x4x4 or 256 different
words if we increase this to 5 letters it will be 1,024 different words,
6 letters 4096.
Now, given that DNA really isn't a book made of paper and ink and we now know that the words are four chemicals what the heck is it written on? Another analogy: it's like a very long thread wound up on a spool, DNA can you imagine that an encyclopedia written on a spool of thread!! Mind boggling ain't it?
Well lets go back to the book analogy, all the information (blueprint) that makes up a cat or any living thing is stored on these funny books, volumes of our encyclopedia, stored on shelves called chromosomes, the books we call genes. We often refer to these genes as basic units of inheritance; agouti gene, polydactyly gene etc. So far so good right? Each gene or book has instructions for specific protein production. These proteins specify actions or inaction that determine appearance of our cats or their phenotype.
So typically in cats we see 38 chromosomes (diploid number ), 19 from each parent ( haploid number ) . So for any given genetic trait we see in our cats each of it's parents contributed one version of that for that trait to the offspring these things must have a silly name of course they are called alleles. They could be the same or close enough to the same version to make baby look like Mom and Dad, or they could be different alleles ( gene versions) and wind up looking like Mom but not poor Dad.
I'm just pickin' on Dad it could be the other way around too. Since all of these protein building instructions came from both parents half from Mom and half from Dad. The offspring will have inherited all of their alleles from the Mom and the Dad this collection of assorted alleles is the genetic make up of the offspring or the genotype. This is what tells the baby what to look like ( phenotype ). Environmental factors can influence this as well but if we take care to not spill coffee on our any of the books in our kitty's encyclopedia while they are sitting on the shelves we have few worries of environmental factors grossly affecting our wee ones.
Allen Prichard
Baby Bob's Cattery
(520) 536-2203
babybobs@cybertrails.com
