Learning by breeding.....

Breeding is for me a creative art form. It is what I have always wanted to do. I enjoy paying close attention to minute detail, part of that fascination I have always had with the fowl. In fact the breeding of specific matings has, for me, become the equivalent of lab and field work for a scientist.

Breeding is not quite the same thing as genetics. Genetics seeks to understand the processes of inheritance and development, while breeding seeks to modify an organism with specific preconceived goals in mind. My work takes in elements of both. I seek to understand genes that belong to the wild-type, in the case of the chicken, two wild-types, with the goal of re-creating the unknown wild-type in it's entirety. That's right, I want to create something that went extinct at the dawning of civilization, a regular Jurassic Park.

Sound impossible, does it? Well, maybe, but it's been a great motivator. And I'm sure to develop at least a very close approximation if not the exact creature. With the breeding I learn more with each generation, gain a more nuanced understanding, which modifies my goal somewhat. The way I like to put it, The more I learn the closer I get, and the closer I get the more I learn. I am not so concerned with the minutia of the inheritance as with what would make the most sense in a natural creature, would recreate a natural balance in form and behavior.

As an example, it's not too much of a stretch to consider the Red Jungle Fowl a flyer and the Malayoid a flightless runner. So what would you be looking for? The Jungle Fowl would be light for it's size with hollow wing and leg bones, a light frame, and capable of very swift flight. The Malayoid would be comparatively heavy for it's size with marrow filled bones and massive thighs and that's what we find in the Asiatic games.

 

 This is a Great Indian Aseel cock. As an example of balance I will point out that these Asiatics often carry their wings out laterally from the body. I learned from my Saipans that this trait allows the wings to cover the massive thighs and long legs. It looks odd, but serves a purpose, so must be part of the Malayoid phenotype.

                                                Thank God for pictures.

I would expect the back to be rounded somewhat, emu-like, in a running bird. Many Asiatic Game have an unusually upright carriage which I do not consider natural. The Red Jungle Fowl, on the other hand, does have a straight back.

Perhaps the best take home lesson here is to get to really know your birds. It would probably be good for every student of poultry science to, at some point, care for his or her own birds, shoulder the entire responsibility for say a year or so, for the productive lifetime of the bird.

The thing I admired most about Dr. Cole was that he actually did the hands on care for all the birds at Cornell, was a very practical man. In fact the university kept him on long after retirement for the express purpose of caring for the college poultry stocks.

How to analyze a hybrid.....

So, let's consider the problem we face. If the chicken is a two-species hybrid as I've stated, how do you prove it? What is the evidence?

Firstly, the differences between the Asiatic Game and the Red Jungle Fowl are obvious, but to analyze these two forms against each other directly is virtually impossible. Even though comparison can be a useful form of measurement, it is too complex a problem to solve by comparing the whole birds. Good men have tried and fallen short.

                     This is a genuine Red Jungle Fowl hen in my possession.

This is the head of another bird also in my possession, half Saipan, a breed closely allied to the Japanese Shamo, the mother being one of my small sized project birds.

One individual, Dr. Frederick B. Hutt, one of the most respected men in the Poultry Science of his day and with whom I have an indirect connection through his student and lifelong colleague, my Poultry Genetics and Anatomy teacher at Cornell, Dr. Randy K. Cole, did manage to frame the origin problem in a reasonable and systematic way. There is either a monophyletic origin or a polyphyletic origin to the fowl. If one is inclined to support the polyphyletic theory, he or she "may choose between two possibilities. Either (1) all fowls are descended from two or more of the four existing wild species of Gallus; or (2) the Mediterranean breeds may have had such an origin, but some other ancestor now extinct gave rise to the Asiatic breeds." pg. 10 Bingo!

His book, Genetics of the Fowl (1949), was known as "The Breeder's Bible" and for good reason. His writing style was relaxed and informal, very readable, not unlike the science writers of today, belying the wealth of information he provided. It is still available through Norton Creek Press.
http://www.nortoncreekpress.com/genetics_of_the_fowl.html

Alright then, so how do you solve a complex problem? You first break it down into it's most elemental components, solve these simpler parts, "disassemble and solve" as the engineers say, then reassemble and see what you've got.

An easy problem, right? No, not really. If it were an easy problem, someone would have figured it out since Darwin first tackled it nearly 150 years ago. No one need feel embarrassed for missing it.

However, and this is an edit (2019), what has been missed is the fact that the single alleles, genes, which follow and that were first studied more then 120 years ago are now understood to be far more complex then formerly realized. They are not simple point mutations. These are evolved genes differing by many base pairs from the accepted wild-type alleles. As such they could not possibly have come about in the relatively short time (8000 + years) since domestication of the fowl. This and this alone is the smoking gun. Complex genes/alleles that are not found in the Red Jungle Fowl had to come from somewhere else, i.e. another species, long before the chicken was ever domesticated.

The phenotypic traits reviewed by Dr. Hutt provided the basic pieces I needed. Many are all or nothing characters determined by single alleles. I liken them to pieces of a jigsaw puzzle. Here we have many pieces from two separate and distinct pictures all jumbled together needing to be sorted out. Luckily, we have one more or less complete picture in the Red Jungle Fowl. I say more or less because over the last ten thousand years or so there has certainly been considerable introgression of the domestic fowl back into the wild. Being as nature is an unforgiving taskmaster, the observed changes in the wild form would tend to be rather slight.

Phenotypic traits can be sorted in one of three ways. They can belong to the Red Jungle Fowl, wild-type alleles, easy to identify. The remaining characters can then be considered as either disadvantageous point mutations (most likely) under domestication, or as more complex alleles, possible candidates for a second wild-type belonging to the Malayoid genome.

Like any puzzle, the first pieces are going to be the hardest to recognize. I had to look at traits and decide whether there was the slightest possibility that one trait or another could belong to the ancestral Malayoid, sort of a "pin the tail on the donkey". This was in no way a proof to be sure, only a possibility. I had to muster all the evidence I could find no matter how seemingly trivial, search for the slightest relevant connection. In fact I used to call it my trivia collection, anything to perfect my Malayoid model, but as you can imagine it has grown into a fair store of information over time.

Examples. One very good candidate gene has already been discovered, Dr. Laden, you know this one; the yellow skin gene. Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken
 http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1000010

It is reasonable because it inhibits the breakdown of carotinoid pigments in the skin, shank and beak, but not in the liver where the breakdown is necessary for Vitamin A metabolism. It could very well belong to the flightless Jungle Fowl.

For another example, two actually, look at the comb of "Brow" in the above picture. It is not a comb at all, only a flat cushion. The Red Jungle Fowl hen has an upright single comb. It is much better developed in the cock bird.

The cushion comb differs from the single comb at two distinct loci. One manifests as the so-called pea comb, the other as the rose comb. The flat comb is reasonable, more so than either the pea or rose alone.

This bird has the cushion comb, yellow skin, and two more; crest and 'beard and muff'. On a loose feathered more Red Jungle Fowl type of chicken, these can appear monstrous, especially the crest which is often associated with a noticeable knob, a cerebral hernia. On this hen, half Cornish bantam in breeding and close feathered as are all Asiatic Games, the crest and beard look quite natural.

Am I making sense so far? Please question me if it is not clear. I will gladly answer any and all, and thanks for reading this. Take care.

 

 

 

 

So what is a chicken anyway???

Ok, so I might have given it away in my first post, The Red Jungle Fowl is ancestral to the chicken. But that is only half the story, quite literally. And just what is a Jungle Fowl?

A Jungle Fowl is a type of pheasant, Phasianidae Family, including four living species which occur in India, Sri Lanka, Southeast Asia and Indonesia. (Wikipedia) These are the Red Jungle Fowl, Gallus gallus or Rooster rooster :-), the Grey Jungle fowl, Gallus sonneratii, the Sri Lanka Jungle Fowl, Gallus lafayetii, which is more politically correct than Ceylon Jungle Fowl, though I still like the old name better, and the most aberrant of the four, the Green Jungle Fowl, Gallus varius, of Java and other islands. The Green is particularly interesting because it is a littoral feeder, frequents shorelines, and has the ability of extended flight over open ocean to reach small islands in it's range.

                                          [Courtesy of Wildlife Images]


The other Jungle Fowl, I assume, are like the typical  Ring-necked Pheasant, Phasianus colchicus, capable of limited flight only. In fact, I have observed chickens, the aforementioned barnyard bantams, fly in an identical manner; an explosive takeoff followed by a leveling off 'flap and glide' mode which can cover a considerable distance. Fascinating.

But most chickens don't fly, do they? Size is a major factor here, small chickens can get airborne much more easily than large breeds.

So, getting back to the chicken, it has been generally assumed that the Red Jungle Fowl is the sole ancestor of the fowl, being that it is the only Jungle Fowl genetically compatible, and being very close in appearance and habit. That another species could be involved has been until recently pretty much overlooked, harking back to Charles Darwin in The Variation of Animals and Plants under Domestication 2nd ed. 1875. He doubted that another parent species (of the more atypical breeds of chicken) could have formerly existed and then become extinct:
"But even if it be admitted that G. bankiva (Red Jungle Fowl) is the parent of the Game breed, yet it may be urged that other wild species have been the parents of the other domestic breeds; and that these species still exist, though unknown, in some country, or have become extinct. The extinction, however, of several species of fowls, is an improbable hypothesis, seeing that the four known species have not become extinct in the most ancient and thickly peopled regions of the East. There is in fact, not one other kind of domesticated bird, of which the wild parent-form is unknown, that is become extinct."
 This last sentence is a little confusing. He ends the paragraph:
"From these several considerations we must look to the present metropolis of the genus, namely, to the south-eastern parts of Asia, for the discovery of species which were formerly domesticated, but are now unknown in the wild state; and the most experienced ornithologists do not consider it probable that such species will be discovered." (Chapter 1. VII. Fowls)
However, he does admit by the end of the passage:
"Finally, we have not such good evidence with fowls as with pigeons, of all the breeds having descended from one primitive stock...... In the case of pigeons, I have shown that purely-bred birds of every race and the crossed offspring of distinct races frequently resemble, or revert to, the wild rock-pigeon in general colour and in each characteristic mark. With fowls we have facts of a similar nature, but less strongly pronounced....."

So here is where I break with Darwin and state plainly that the chicken is indeed a two-species hybrid. Furthermore, the 'other' parent species is also indeed extinct. What Darwin did not consider was the possibility of an island bound Jungle Fowl. Let me explain.

There is a very distinctive class of breeds known collectively as Asiatic Games. These include the Japanese Shamo, Indian Aseel and others characterized by large size, usually a pea comb, upright carriage and a coarse heavy browed head. They are often very tall.

                                  This is a Shamo belonging to a friend of mine.

These are definitely not typical Jungle Fowl. The difficulty in analyzing such a bird is that they are hybrids, not the original pure species. I have managed to do so by comparing individual traits.

All breeds worldwide fall along a continuum from mostly Red Jungle Fowl to mostly this other 'Malayoid' type after the better known Malay breed from England.

An obviously flightless bird like this could only have evolved on an island free of mammalian predators. Yet it had to be closely allied to the Red Jungle Fowl to have preserved a compatible genome under geographical isolation.

The most likely scenario was this. The bird was discovered, many thousands of years ago, proved easy to tame and rear. Remember island birds tend to lose their fear of man. It was taken to the mainland where hybridization took place with wild Red Jungle Fowl. I know the original Malayoid was nowhere near as large as the present day Asiatics making crossing a possibility. Meanwhile, the original population on the island of origin would have become rapidly extinct, as usually happens after man discovers any vulnerable species.

I'll explain how a domestic hybrid can be broken down and studies in my next post. Promise.

Starting at the beginning.....

Everyone knows what a chicken is, right? That most useful of domestic productions and, without a doubt, the single most important bird in the world as far as mankind is concerned.

This is an article in Discover magazine from June 1988, by Richard Conniff. They were well integrated into industrialized agriculture by then to "become our cheapest and most abundant source of animal protein."
More recently I read where more than ten billion chickens, mostly for meat, are produced in the United States alone in one year. So yes, I would say the chicken is right up there in importance. That's a lot of chicken McNuggets.

The chicken has been with us for a very long time, remains have been found in China going back 8,000 years. They have been carried by man everywhere outside the high Arctic, even traveling with the Polynesians to cross the pacific, actually reaching south America at least one hundred years before Columbus.

But maybe I'm putting the cart before the horse here, should give you a little personal background first.

I've been at this awhile, studying the fowl. When I was five back in 1952, we had just moved to the country from Buffalo, NY, and my father, wishing to expose us to a wide range of experiences, brought home a sitting hen from a neighbor. I can still remember seeing those baby chicks the day they hatched, so fascinating. I marveled at the colors, some black, some dark red, and a couple the expected yellow. That was it for me. I became fixated on the chicken.

I have to laugh when I think about this focus thing because it runs in my family, from my maternal grandfather, a civil engineer, to my mother to my brother and me. Then to at least two of my sons and daughter and two grandsons that I know of for sure. I am probably the worst of the lot, have never had a good working memory, very likely aggravated by the fact that I read way too early, got in the habit of always referring back to a word or name instead of trusting my memory.
As the twig is bent....

So, where were we? Origins. That's my interest, and not only the chicken, but the cow as well and a passing reflection on the other domestics. I suppose I could have become some kind of naturalist, always checking out the local fauna and things; fish, frogs, newts, clams. Loved watching things grow; animals, plants, kids. Maybe that's why I ended up with such a large family for this day and age, totally impractical for sure, but I wouldn't change it for the world. Seriously.


Anyway, I would imagine my chickens and the neighbor's cows as wild creatures. What were they like before man tamed them?

We had a local phenomena back then before dairy farm regulations got so strict known as barnyard bantams. They probably started out as pets somebody had dropped off. The farm was like it's own little contained ecosystem and it was a survival of the fittest. There was food enough and warmth generated by the cows in winter, and cats. I really doubt if the cats really did all that much to control vermin to any great degree, but I'm quite sure they drove the evolution of the feral bantams. They were great little mothers. All the wild instincts were there. And they could fly very well. Of course I would bring some home, picking them off their high perch over the cows at night.


I bred one of these hens to a 'game' rooster one year. She had just come off her nest in the small barn behind our house and was keeping her chicks very close. Our cat sought to investigate, the picture is burned into my memory to this day, the hen became a blur of wing and feathers, flew behind the cat right on it's tail clear around the barn and out of sight. Next thing I knew she was flying back, flying, not running, back to her babies.

The colors of the barnyard bantam were varied, but tended towards the so-called black breasted red of the ancestral Red Jungle Fowl. It is a sexually dichromatic pattern, only the cock is BBR, the hen being cryptically colored and the chicks with pretty chipmunk markings of their own.

I bred from the above game x bantam cross for several years, ended up with some outstanding birds not too different from the half-junglefowl pictured above with my granddaughter Mary.


To be continued....