My contribution to an online chat, slightly edited:
I can share something REALLY neat from my shelf BTW… I have a copy of a small textbook (1926 printing; originally copyright 1917) called “THE THEORY OF EVOLUTION” with subtitle “WITH SPECIAL REFERENCE TO THE EVIDENCE UPON WHICH IT IS FOUNDED” (caps in original) by William Berryman Scott.
Now, it’s full of the usual stuff (comparative anatomy, embryology, geographical distribution, etc.) BUT starting on page 73 I read about something I had never heard about before: “EVIDENCE FROM BLOOD TESTS” (caps in original)
It references work by a “Dr. George H. F. Nuttall of the University of Cambridge” (I actually found a pre-WWI copy of Nuttall’s book at the University of Saskatchewan library)
What is done is you take a blood sample from a species (e.g. Human) and let it sit for a few minutes in a dish; the cells will coagulate, but the nearly-clear serum remains. Then you inject the serum into a rabbit over the course of a few days to produce antibodies. Let the rabbit live for a few more days, kill it and then extract its blood and separate out the serum. If you injected human serum into the rabbit, the rabbit’s serum is now “anti-human” serum.
Apparently the antibodies in the anti-human serum are EXTREMELY specific to human blood; if you take even a small amount of blood (fresh, dried as a stain or even “putrid”) and make a dilute solution of it and then add the anti-human serum, it will give a white precipitate if it was human blood, but NOT if it was from other species.
They mention how it was useful in forensics: “In some countries, notably in Germany and Austria, this test has already been adopted by the courts of justice and has been found extremely useful in the detection of crime.”
But here’s where it gets AWESOME…
It was noticed that the precipitation was obtained, though “weaker and slower” in very closely related species (horse and donkey is the example given). Nuttall’s insight: “By using stronger solutions and allowing more time, quite distant relationships may be brought out.”
Nuttall and his fellow researchers did thousands of blood serum tests; the ref given for the publication is “Blood Immunity and Blood Relationship” published 1904.
Update: I just found that archive.org has two copies scanned!
Anyway, getting back to Scott, he says that the blood serum test results (while “highly interesting and important”), give few surprises since it confirms conclusions drawn from other methods (independent confirmation is always good news in science :)
Nuttall marvels “that a common property has persisted in the bloods of certain groups of animals throughout the ages which have elapsed during their evolution from a common ancestor, and this in spite of differences of food and habits of life.”
My analysis: He is probably seeing reactions to proteins like serum albumin; the exact makeup of these proteins will vary from species to species because of genetic differences… so a century ago they discovered a way to indirectly compare the similarity of genes across distant species! :D
Scott condenses Nuttall’s results into 11 points, which I will further summarize ;)
(1) if you use strong enough solutions and enough time, you can get reactions from any mammal/anti-mammal pairing.
(2) In decreasing reactivity to anti-human serum:
* “Man-like Apes” (so, the great and lesser apes; chimps, gorillas, orangutans and gibbons)
* Old World Monkeys
* New World Monkeys and Marmosets
* Lemurs gave basically no reaction.
Point 2 reminds me of http://en.wikipedia.org/wiki/Human_ape_hybrid specifically this: “In 1977, researcher J. Michael Bedford discovered that human sperm could penetrate the protective outer membranes of a gibbon egg. Bedford’s paper also stated that human spermatozoa would not even attach to the zona surface of non-hominoid primates (baboon, rhesus monkey, and squirrel monkey), concluding that although the specificity of human spermatozoa is not confined to man alone, it probably is restricted to the Hominoidea.”
Oh, also in relation to point 2, see one of the best (and sadly mostly unknown, which is why I put a copy on my personal site) illustrations of how closely humans are related to the great apes:
http://members.shaw.ca/Limulus/files/chr2/ A paper from 1982 showing comparisons of stained chromosomes…
(3) anti-carnivore serums react strongly among carnivores, but weakly with non-carnivores; among carnivores the strongest reactions are “amongst the more closely related forms in the sense of descriptive zoology.”
(IOW the testing supports the monophyly of Carnivora and morphology-based phylogenies within it)
(4) In decreasing reactivity to anti-pig serum:
* Family Suidae (pigs, boars, warthogs, etc.)
* ruminants and camels
Also, anti-llama serum reacts “moderately” to camel blood and the deer family (Cervidae) show “close relationship” with “the great host of antelopes, sheep, goats and oxen” (family Bovidae)
Now, let me say that when I read that mention about whales, I was *floored*. It wasn’t until almost a *century* later that we got strong genetic evidence for whales being related like that; see Figure 5 and related text on http://www.talkorigins.org/faqs/molgen/
(5) anti-whale serums only strongly reacts with other whales; slight reaction to pigs and ruminants.
[I really should go back and check to see if they did whale-hippo tests; if they didn’t, they were SO close to making a major discovery…]
Also, regarding whales again: http://en.wikipedia.org/wiki/Cetartiodactyla
(6) a close relationship between all marsupials “with the exception of the Thylacine or so-called Tasmanian Wolf”
sad sad ;_; http://en.wikipedia.org/wiki/Thylacine
(7) strong anti-turtle serum reacts most only with the bloods of turtles and crocodiles; lizard and snake reactions are “almost negative.” Also, “with the egg-albumins of reptiles and birds a moderate reaction is given.”
(8) anti-lizard serum reacts most with the blood of lizards “and reacts well” with the blood of snakes.
(9) based on 7+8 we get:
“results for which palaeontogical studies had already prepared us.”
I note with great interest regarding turtles that there is *still* controversy regarding the exact position of turtles and only in recent years do we see support for a phylogeny similar to the above instead of turtles distant from all the other groups…
When I was at University I was taught that turtles were only distantly related to the diapsids! 1904 science FTW! :D
(10) Crazy amount of lab work: “Tests were made by means of anti-sera for the fowl and ostrich upon 792 and 649 bloods respectively.” The result was that bird/anti-bird reactions were much stronger than mammal/anti-mammal ones; no specific bird group relationships could be drawn.
(This is quite interesting; it is very much in line with the fact that mammals as a group are older than birds…)
(11) The horseshoe crab is “problematical”; while aquatic like crustaceans, embryological evidence links to the terrestrial spiders and scorpions. The blood tests support the latter.
The rest of the section talks about how we can’t determine exactly how closely related two species are based on the relative precipitation rates (e.g. ostrich and parrot react more than wolf and hyena) “Like all other anatomical and physiological characters, the chemical composition of the blood is subject to change in the course of evolution and these developmental changes do not keep equal pace in all parts of the organism. It is the rule rather than the exception to find that one part of the structure advances much more rapidly than other parts” but even if we keep this firmly in mind, “these tests are very remarkable.”
The last paragraph is like a time capsule to be opened this century when we finally can fully sequence genomes and directly compare them:
”The blood tests have brought very strong confirmation to the theory of evolution and from an entirely unexpected quarter; they come as near to giving a definite demonstration of the theory as we are likely to find, until experimental zoology and botany shall have been improved and perfected far beyond their present state.”
Update Aug. 4, 2011: Shared antigenicity between the polar filaments of myxosporeans and other Cnidaria. Using a rabbit antiserum, a link between Cnidaria and Myxozoa is further suspected…