“...Then all of the chronicles and achievements of man fall humbly into the history and perspective of polymorphous life; all our economic competition, our strife for mates, our hunger and love and grief and war are akin to the seeking, mating, striving and suffering that hide under these fallen trees or leaves, or in the waters, or on the boughs.”
Will Durrant poetically describes the diversity that exists on this impartial planet. The most diverse and complex members belong to a group called metazoa in scientific terms; animals in lay. The term animal can be misleading due to culture, but humans and fish, dogs, cats, and humming birds, butterflies and worms all belong the group Metazoa because they are all evolutionarily, although very distantly related.
METAZOA Paps et al. 2009
Phenotypic diversity and differences exist because they are the fabric of natural selection and evolution; the DNA housed in the cells of every living thing produces the phenotypes. However, molecular biologists have thought long and hard about the relationship between complexity and total amount of DNA and have come to the conclusion that the total amount of DNA is not what gives rise to complexity or diversity. Advances over the past decades have cleared up some of the confusion. For example, the genome of the multicellular eukaryotic microbe, Amoeba proteus is 100X the size of ours; humans.
Amoeba proteus http://www.realmonstrosities.com/2011/01/amoeba-proteus.html
Conversely, many other microbial eukaryote genomes are 100X smaller than ours. Another problem with the the size matters hypothesis is that complex animals such as octopus, humans, and elephants have less streamlined genomes than we would expect; an economical use of the DNA. It turns out that our genes are interspersed with vast DNA deserts that don't code for any proteins as far as we know. These three conclusions are called the C-value paradox (Moore G.P. 1984 "The c-value paradox"): Complexity doesn't coorelate with genome size, organisms that look the same often have different genome sizes, and seemingly complex organisms have more DNA that doesn't make proteins than DNA that does.
“A DNA molecule is a long chain of building blocks, small molecules called nucleotides. Just as protein molecules are chains of amino acids, so DNA molecules are chains of mucleotides... The nucleotide building blocks come in only four different kinds, whos names may be shortene to A, T, C, and G. These are the same in all animals and plants. What differs is the order in whih they are strung together. A G building block from a human is the same G building block from a snail. But the sequence of building blocks in a man is not only different from that ina snail. It is also different - though less so - from the sequence in every other man.
Our DNA lives insid our bodies. It is not concentrated i a particular part of the body, but is distributed among the cells. There are about a thousand million million cells making ap an average human body, and, with some exceptins which we can ignore, every one of these cells contain a complete copy of that body’s DNA. This DNA can be regarded as a set of instructions for how to make a boy written in the A, T, C, G alphabet of nucleotides. It is as though, in every room of a gigantic building, there was a book-case containing the architect’s plans for the entire building. The ‘book-case’ in a cell is called the nucleus. The architect’s plans run to 46 volumes in human - the number is different in other species. The volumes are called chromosomes.”
If genome size really doesn't matter, complexity must depend on how the DNA is used; how the DNA is regulated. When all of the known modes of gene regulation are combined, some extreme variations in proteins are possible. However, of all known modes of gene regulation, alternative splicing represents an animals number one mode of increasing the number of distinct proteins (Nilsen & Gravely 2010); of producing multiple mRNA transcript from the same gene. 95% of human genes are alternatively spliced, and the single gene Dscam in Drosophila makes over 38,000 products from it's 95 alternatively spliced exons.
