Materials for the study of variation treated with especial regard to discontinuity in the origin of species Kindle Edition

Good edition

William Bateson's book, Materials for the Study of Variation, Treated With Especial Regard to Discontinuity in the Origin of Species" is a classic book of science that has stood the test of time, although this book is not particularly easily readable and is not recommended as general reading for most.

What is truly fascinating is content of this book, and the story of William Bateson.

Consider this: here is a person-scientist over 100 years ago, in 1894, long before the recombinant DNA techniques, including sequencing of genomes and the understanding of gene regulatory regions and function at the molecular level, documenting, that variation in morphology and structure among the different species is often discontinuous, not continuous.

After years of compiling and categorizing the variations of animal design, cataloged in this 1894 book, William Bateson documents that when comparing the different species variation is discontinuous; species often vary by abrupt changes or jumps, termed saltations. Disagreeing with Darwin ... an icon even at Bateson's time ... about the nature of variation that are all around us in the animal kingdom.

Although Darwin knew and discussed abrupt variations or saltations, when addressed by his friend and supporter with questions about how these abrupt changes might contribute to the processes of natural selection and what role these abrupt changes have in evolution, Darwin said, "non saltum natura." Meaning, natural selection does not incorporate saltations or abrupt changes, even in events to form the different species, termed speciation.

What is the evidence for saltations or abrupt change and are they incorporated into the various species?

In Materials, Willliam Bateson provides comparative anatomical evidence suggesting that morphological structures and organs appear in particular positional relationships, that is, structures are positioned either forward, "from behind moving forward" or backward "from before moving backward" along the length (axis) of the animal, when comparing the body plans of various animals.

To illustrate Bateson's comparative positioning principles, consider the positioning of mammary glands in several vertebrates. In a comparison along the axis from the head to the toe, with the head at the beginning and the toes at the end, the mammary glands of primates including humans occur usually as single pair at the thoracic (chest) region, while those of a canine occur as pairs starting at the thoracic region and extending along the abdominal (stomach) region in two lines. Those of a porcine (pig) occur commonly as either sets of six, seven or eight in two rows extending in a line from the thoracic region to the abdominal region.

So, when comparing the positions of the mammary glands between a human and a canine from the head-to-tail, from beginning to end, and considering the human as the ground-state animal form, or model to be compared to, Bateson would say that the additional sets of breasts of the canine have been re-positioned forward along the length the animal body. The mammary glands have been re-positioned from a behind position to a more forward position, "from behind traveling forward" a forward homeosis.

Conversely, when considering a bovine (cow) as ground state animal form and human in comparison, the positions of the human breasts are re-located backward along the head to toe axis, "from before traveling backward", a backward homeosis.

Bateson derived these terms from homoeosis (now homeosis), from the greek for homoeosis "becoming like" meaning the something has been converted in to the likeness of something else.

As an additional example to illustrate Bateson's concepts, consider the visual effect of a second set of mammary glands occurring in a human that are positioned on the lower thoracic region than the normal first set of mammary glands. An extra set of mammary glands, termed supernumerary mammary glands (more than the usual number, or super number), occurs in small percentage of humans. And usually occur as an additional set of mammary glands positioned lower on the thoracic region (see picture). In this case, the lower thoracic region has undergone a partial homeosis, it now contains an extra set of mammary glands. So visually, this region, now has some characteristics of a human upper thoracic region, the lower chest region now contain a set of breasts. In Bateson's terminology, this constitutes a forward homeosis, "from behind traveling forward."

Another way, sort of, to view Bateson's, "Materials for the Study," is to consider this study as a mega exhaustive mutational study long before the capability to perform large mutational studies that require the introduction of mutations induction by modern genetic techniques.

Bateson examined all the variations (mutations) available, focusing on comparisons within a species (intra-species) and as well comparing the variations between species (inter-species). Focusing on intra-species variation, because the most likely arising variations within a species might be the most likely variations that can become a new predominate animal form or species. Focusing on inter-species variation, because these animal forms might conversely be reflective of the most likely intra-species variations.

In this manner of thinking current animals forms are the long-long time decendents of a intra-species variation that has occurred at some prior time and has eventually led to speciation, resulting in a new predominate animal form today.

So here is the remarkable climate today.

On one side of the evolution debate there is one group, the intelligent design ID community that has pointed to the abrupt changes as evidence that evolution theory is incorrect. The main thrust of their argument is to refute all of evolution. The ID theorists often point to holes in the fossil record for transitions of animal form. And on the other side of the evolution debate has been predominately another group, the Darwinists, comprised of a majority scientists who have mostly casually dismissed as unimportant the evidence pointed to by Bateson, and his thinking for over 100 years.

If the process of evolution gradualism is completely correct, then what of the positioning and number differences of the mammary glands between human and our close friends the canine and the feline? Are we to ignore these location and numerical differences and suggest that in each animal the mammary gland evolved?

The story of positioning, an intriguing mystery may be starting to unravel.

During the later part of the 20-century a multi-year mutational study by E. B. Lewis identified one set of genes, involved in positional location, the Hox genes.

Mutations or alterations in these genes affected the locations of organs in the fruit fly Drosophila and altered the adjacent regions or segments, such that segments were changed into the likeness of another adjacent segment, homeotic changes. In this study, more abdominal segments that normally contained only wings or halteres (primative stabilizing wings) would now contain thoracic structures, legs. In a head-to-toe analysis, this is a forward homeosis, "from behind moving forward" the legs are normally on the thoracic segment, but when an alteration is introduced the legs appear on the following segment as well.

So what does this all mean?

This all suggests is that there is an underlying unseen partially redundant positional code that is required to position structures correctly, and this positional code is set up during the very early formation of the animal (gastrulation) or the insect (germ band extension) and is subsequently acted upon during embryonic development.

Today's experiments are supporting William Bateson's ideas of homeotic changes. William Bateson's refusal to ignore the evidence despite stiff opposition may make him a person 100 years ahead of his time. Endless Forms Most Beautiful: The New Science of Evo DevoThe Structure of Evolutionary Theory