Mosaics

 

Somatic Mutations by Dr. Lester Paul Gibson Somatic mutations are common in plants.  Many of these have been propagated by plant breeders and account for a lot of the plant variations on the market.  Particularly of the plants that do not produce an abundance of seeds or that, produce seeds that are so diverse in their genetic traits that the desired trait is hard to get.  Most of our fruit trees and many of our shade trees are propagated from grafts or cutting to keep the same genetic characteristics.  These usually are propagated from somatic tissue.   Some plants like Coleus are noted for their somatic mutants and easily propagated.  I have seen somatic mutations on lots of plants that produce completely new varieties and thus somatic mutations are converted to new genetic status.    But that is another story since we normally cannot do that with animals. In animals, we see somatic mutations but they are usually not  transmissible by tissue propagation.  However, tissues from these can be grown in the proper medium.  Somatic mutations include moles, warts, cancer, stray colored hairs, stray feathers, etc.. Mosaic areas can occur on varying amounts, sizes, and areas on animals just as they do in plants.  Part of these can be somatic but most are apparently genetic in origin.   The single feather or scattered small patches of feathers can be either genetic or somatic but by definition they are all mosaics. When we see what appears to be a somatic mutant, it many times turns out to be by selection, a genetic mutant.  A couple instances of the latter readily come to mind:  Way back when, a German family was rearing green finches from the Canary Islands, one bird turned up with a single yellow flight feather.  By inbreeding, they were able to increase the yellow feathers until they had an all yellow bird, which is the ancestor of our yellow canaries. A number of years ago, I visited with Elsworth Kistler in Pennsylvania.  He had an Archangel turn up with a white spot about the size of a silver dollar in the middle of its bronze chest.  I saw the bird and tried to buy it from him.  He wanted to breed more of the same and did not want to part with it.  He did this but the white was now about half the bird.  I purchased some of these from him.  Breeding them together, he and I produced some all white with black tails.  Breeding these together produced some all white birds.  When these all white birds were bred back to full colored birds the white completely disappeared so it was a recessive white that acted as a migrational white just as the yellow was a migration mutant in the Canary. Most somatic mosaics in our birds show up as a small spot or feather on the body.  If you have an ash red bird, a white bird, or an Almond with small spots or feathers other than the color they ought to be (blue or black on red ground) (red on blue ground) etc. they probably are somatic mosaics. Many almonds will have a group of feathers forming a spot somewhere on the body and these are probably somatic and not bipaternal. A somatic mutation can occurs in any cell (body cells) except the reproductive cells (genetic cells) i.e. genes on the chromosome which result in the reproductive cells (egg and sperm). In warm blooded animals it is fairly clear cut; unless the trait can be reproduced genetically it is considered to be somatic.  In plants, this becomes blurred because somatic cells, as demonstrated above, can be selected to produce a new plant which can then produce its own reproductive cells and thus the somatic mutation becomes a genetic. In Insects and other cold blooded animals the action of mutations is blurred by the multitude of ways the organism can be, and is, affected by the environment in the very broad sense.  Many insects can reproduce parthenogenically until the environmental conditions become stressful and then reproduce genetically.   Many mollusks and annalids reproduce by being hermaphroditic.  Some mollusks are born female and after a number of years change to males so that sexual reproduction can be accomplished.  Some fish may change sex in the absence of available males in the population.  Alligators and Crocs reproduce sexually but the sex of the hatchling is dependent upon the temperature of the eggs during incubation.   All of these things have a bearing upon the picture as to whether a mutation in an organism can be called somatic or not.   As you can see there is no simple answer.  Bet you did not want to know all of this when you asked. Dr. Lester Paul Gibson

Bipaterity sperm Mutations by Dr. Lester Paul Gibson I think in order to form a basis of understanding for the possible formation of what we call a mosaic pigeon; we must start at the cellular level. At one phase of the cell division, there occurs a different type of cell division from mitosis.   This type of cell division is called REDUCTION DIVISION which forms the germ cells or gametes.   This formation of gametes is known as maturation. We know that normally a new individual is started by the union of two gametes, a sperm cell and an egg cell.  Sperm cells are formed by two cell divisions.   Two primary spermatocyte chromosomes become paired closely in what is known as synapsis.   Each splits in reduction division so that now there are four chromatids (a tetrad).   These separate loosely and one from each dyad goes to each end of the cell and now the cells contain only 1 chromosome of each pair.   The other two spermatocytes (the two not used above) divide by mitosis and form spermatids.   These form sperm without further division. If during the reduction division part of each exchange sections with the other; we have what is known as a chiasma. THIS IS WHAT WE CALL A CROSSOVER. In the formation of the egg from potential egg cells, a similar series of events takes place.   The only difference is that instead of the process producing 4 gametes (like the sperm production), three of the four are normally small and disintegrate.   We call these POLAR BODIES.   The fourth gets all of the cytoplasm and becomes a mature egg.   Each of these cells will have one chromosome of each pair, the difference is that only one gets the cytoplasm and the others do not get any. If during this process instead of only one remaining, one of the others (a polar body) should also get some of the cytoplasm or the division is not complete and the polar body does not deteriorate; then we get a dual cell egg (a bipolar egg).  In this case, each of the two poles may now become  fertilized by a different sperm (bipaterity). Depending upon the size and viability of each; the area of mosaicism may be half or somewhat less than half of the resultant organism. Chromosomal aberrations occur in several ways but lets reserve our discussion to those that may produce mosaics.   One type is called non-disjunction in which during cell division, both chromosomes go to the same end of the cell and thus producing a cell without a chromosome and one with both.   This is not a theory because it is known to happen.   Certain resultant combinations do not produce viable embryos and thus do not live and others instead of producing diploids may produce triploids, tetraploids, or monoploids for certain chromosomal pairs.   Work with drosophila flies has proven that they can and do occur.  Another type is called translocation (another crossover mechanism).  Another type is called segmental interchange (a double crossover mechanism).  Another type is called deletion (a mutational mosaic mechanism). It has been stated that a cell with three chromosomes cannot live.   That has been patently proven to be false in many insect and plant genetic tests and manipulation results.   It is known to even occur in a number of human cases in the sex chromosomes in which individuals may have the sex configurations of XXX, XXY, XXXY, XXYY, or even XXXXY.     Somatic mosaics can occur anytime after fertilization of the egg.   If early in the development, there may be near 50% of the organism or if later only a few cells. Let's consider the bipaterity sperm theory.   If the sperm fertilize the egg at or nearly at the same time you would get a configuration somewhat like below: __   __   __   __   _________  Sperm A ------------------------------------------   Egg ---  ---   ---  ---   --------------------  Sperm B As the egg starts dividing the Sperm A and the egg would produce cells that become the right half and Sperm B and the egg would produce the left half. In the case of a bird like the half black homozygous Chinese Owl/Sooty Blue bar hetero Baldhead Roller reared by Marvin Lee; the above would work better if we have a bipolar body egg or if you prefer a Siamese egg. _____ ____ _________   Owl sperm for black ----------------------------------   Egg Owl black -----------------  ---------------   Egg Owl blue bar ---   ---  ---   -----------------   Roller sperm for Bh Blue bar This would allow one side to produce the homo Owl side and the other to produce the hetero Owl/Roller side.         I have the mounted bird.   Dr. Hollander assured me that it was a waste of money to have it mounted and preserved because everyone will just say it is a hoax.  The Owl side is completely Owl with all the Owl attributes including the pantaloons and the Roller side distinctly Roller with the distinct hetero Baldhead marking. Even measurements of the beak show one side Owl and the other Roller. I said the bird is question would have the brown (or even dun if it proved to be dun) parts female and the black parts male.   That is a given because the traits are sex-linked.   Keep up the good work. Dr. Lester Paul Gibson

The infamous two-sider 

Mosaic By Ken Davis Yes indeedy, that "two-sider" is a nice mosaic, for sure. But, something more. If you look at the photo's real close you'll see that the birds right side is a spread Chinese Owl, complete with the Frill, the Pantaloon, Owl shaped head, etc... Look at the head-on view.....notice the difference in feet structure, leg structure and length, the total package? Now, the left side of the pigeon appears to be a blue bar Birmingham Roller....but look close....and......in fact.....you will see.....it is a Chinese Owl/Birmingham Roller hybrid! In fact, the whole bird is a Chinese Owl/Birmingham Roller hybrid. "How can that be", you ask? Well I had Doc on the phone for about an hour the other day, and we discussed this individual......I'll hi-light for you: Now, I saw this pigeon at the Oklahoma National in January, along with a thousand other Fanciers. I took many photographs of the bird, (most of which I sent to Doc). I was allowed to handle the pigeon, and I talked with the breeder of the pigeon. He told me the circumstances of how this bird came to be, but I couldn't remember. Well, he told Paul Gibson the same thing, and Paul told it to Doc, and Doc in turn refreshed my memory while we were on the phone. The breeder, (and his Dad), are from Arkansas. They breed flying Birmingham Rollers and Exhibition Chinese Owls. Now, they had all the cocks and hens separated at the time. A hen snuck out of the hen pen, and into the neighboring cock pen, which housed spread Chinese Owl cocks and Brown Bar (true Brown) Birmingham Roller cocks. O.K., now, we were all going over these pictures the other night at the Genetics Meeting at Joe Fraziers Place, and Leon Stephens told us that he knows how this happened; that it was "Bi-Paternity". He said that the Frill and the Pantaloon on the Owl side of the bird are recessive characteristics, so the Mother of this mosaic had to be a Chinese Owl, and was bred by two cocks, a spread Chinese Owl cock and a blue series Birmingham Roller, therefore the mosaic was Sired by two Fathers, hence the "Bi-Paternity".

Well, this ain't what happened! The hen that snuck into the cock pen was a "Brown Bar Birmingham Roller", and she was left in there, or allowed to stay, and she was THE ONLY HEN IN THERE. Now, Frill and Pantaloon being recessive characteristics, how'd they get there? How can they express? Let's address the color part of it. The mosaic individual is spread blue on it's right side, and blue bar on it's left side. Now, the Dam, or Mother to this individual is a true Brown Bar, and she could only have been bred by true Brown Bar Birmingham Roller cocks and spread blue Chinese Owl cocks. Well, if she was "treaded" by both, ("Bi-Paternity"), the mosaic would have been a Brown Bar Birmingham Roller on one side, and a spread blue Chinese Owl on the other side. But it's not! Careful examination of this mosaic reveals that it is phenotypically a "pure" Chinese Owl/spread blue on it's right side, and a Chinese Owl/Birmingham Roller blue bar hybrid on it's left side. So how can this be? The best explanation is "Super Numerary Sperm". That is to say that the Brown Bar Birmingham Roller Dam was bred by a Spread Blue Chinese Owl cock, and that more than one sperm from the Sire penetrated the ovum. And for reasons not totally yet understood, the extra spermatozoa affected the phenotype to the results which we now see. Just this last week, Doc sent me a copy of a paper, "PIGEONS IN GENETICS, FROM DARWIN TO BIPATERNITY", which he sent to Edinborough this past February for publication. In it there is a section titled "LATER PERIOD", and here Doc writes about his beginnings of his studies on mosaicism. He states: "One of the most puzzling genetically phenomena was masochism, which did not seem to be like that in Drosophila. Carl Graefe of Ohio presented me with a mosaic female, basically of wild-type color but with a large yellow patch. Yellow is produced by the combination of autosomal recessive red and sex-linked dilution, also a recessive. The bird's pedigree had neither of those genes, and breeding test with a yellow male produced no progeny showing them. Simultaneous somatic mutation was an extremely improbable explanation. Then Graefe mentioned that the mosaic had been produced in a flock pen, in which yellow males were also present. This fact suggested that the yellow patch might have derived from a different sperm than that producing the zygote. Such an explanation was supported by the early embryology of pigeons--Harper (one of Whitman's students) had observed that polyspermy is a normal feature." Now, this next line is important, so pay attention, and read it over several times....."The extra sperms form an accessory cleavage ring around the zygotic cleavage. I proposed the term bipaternity, and it seems to be to account for most sectorial mosaics in pigeons,".....here comes another very important part.....read it carefully......."though 2 fathers are not generally necessary to provide differences among sperms. A similar explanation is used to account for gynandromorphs in honey bees, and is termed androgenesis." PIGEONS IN GENETICS, FROM DARWIN TO BIPATERNITY, By W.F.HOLLANDER, Professor Emeritus of Genetics, Iowa State University, Ames, Iowa50011. This paper issued at the Department Zoology/Genetics, Iowa State University, February 2001. Not copyrighted

 

A mosaic of Mosaic photos

       
Five Mosaic photos by Michael Spadoni of Geelong Australia

Half Smoky / Blue bar by AL Neese  and a Half Mealy / Grizzle by Larry Davis

 
These two photos of the same bird were taken by David M. Longseth at the 2003 NYBS.
The right wing shield is a blue check while the left side is a dark 'dun/brown' color with heavy black flecks or sootiness. 
This left side may be almond as the sire was an almond bird.