23-7-1986

Dear Bill,

Many thanks for the two editions on Chicken Bone Recoveries, the supplement contains many interesting ideas!

I’d be very grateful if I can get Somes’ papers on blue eggs, when you have the time to photocopy them. I couldn’t find the reference on blue egg layers in Asia at home, but I’ll add it on at the end of this letter tonight, in Geelong, before I post it (the book in Geelong).

I don’t know whether it has much information, but at least it may lead to an original article referring to Asian blue egg layers.

If you hear more on Prof Cawley’s Araucana book, I’ll be very interested in that also.

Oh, yes, you’re welcome to use my letter as you like, though these isn’t much new or unusual in it!

I’ll be reading and rereading the Supplement for a while, absorbing parts of interest, but two things particularly caught my attention.

First, as a taxonomist (this is the study of classifying living things) I must say that the article on Gallus europaeus  is very suspect! The coracoid bone is a very minor one to be basing a whole new species on! In addition, this one bone was only compared to 5 corresponding examples of Gallus gallus and that doesn’t prove a lot! Now, I haven’t seen the bone itself, and birds aren’t my field, but parts of this supposedly different bone are missing, and these are supposed to be among the most distinctive parts. However my comments don’t necessarily mean a lot. I’m only going on that was written. Even so, there are a lot of new names made up every year or very flimsy evidence, and all they generally cause is confusion and argument until they’re rejected, and unless more solid evidence turns up, Gallus europaeus  will be a has-been  very quickly. Which is not to say that there is no such bird, but only that this evidence seems very weak. I certainly wouldn’t put it more strongly until I see the original paper.

The most interesting part of the supplement was the suggestion that Araucanas may be a grouse/domestic fowl hybrid! It certainly has some potential for explaining a number of unusual features.

The comments on ear tufts on pp. 19-20 seem relevant here.

Working with fishes, I have often found, or read about, hybrids which fail to develop post a certain stage. What usually happens when a lethal trait shows itself is that the combination of two different, but poorly matched, genes (from the two different species) do not from a balanced gene which will do what it should, because they are incompatible. When the creature reaches a stage when the incompatible gene combination is needed, it fails, and death or physiological damage may result. Thus, some hybrids always die at a set stage of development, they are lacking genes capable of doing the job they should.

Not all hybrids are lethal incompatible genes may show themselves at all stages of development. Some may prevent the hybrid from even occurring in the first place, while others may not be lethal or even harmful, but may make the hybrid sterile.

Somes refers to ear tufting in Araucanas as the heterozygous expression of a single dominant autosomal gene. In other words, the two parts of the gene must be of two different kinds for it to work. If the gene is homozygous (has both parts the same) the gene is a complete prenatal lethal, i.e. no eggs will hatch!

He also states that even the heterozygous combination in lethal in 20% of cases, however, prenatal death occurs for a number of reasons in poultry, 20% not being so uncommon, so this may not be relevant.

This could possibly be explained by some unusual hybrid gene, requiring two different forms of itself to be united before they can work properly as one. However, it could also be the result of inbreeding (e.g. a lethal recessive).

I’ll try getting hold of the relevant paper, and see if anything is certainly intriguing!

Thanks again for the two booklets. I’ll be thinking and reconsidering a whole lot of information, and I’ll be in touch again soon.

If I can find the reference Sauer mentions Asian blue egg layers in, I’ll write it below.

All the best,

C.O.Sauer, Agricultural Origins and Dispersals, (p.58?), 1952