A Tentative Model for Astrex Genetics, by Helga Vierich

Genetics model for Astrex/ CPlop coat genes

Almost all of the blue and black CPLops glow- like maybe they are or resemble satin animals. I have gone over this systematically. I have been thinking about this for some days now:

Normal Satin Astrex

Gene 1: hair shaft diameter/shape-alleles Sa sa sa/sax

Gene 2 hair shaftcurl/wave-alleles Wa Wa wa

Gene 3 guard hair/ less g/h-alleles G G/g g

Gene 4 Belly/neck curly -alleles bn bn Bn

Gene 5 Body Wave -alleles Ku Ku ku

Gene 6 Curl Solid/Curl spotting -alleles sp sp Sp/sp

Gene 7 Balding kit molt - alleles Bm Bm Bm/bm

Myohmy sasa wawa gg bnbn kuku spsp BmBm

China Doll sax/sax wawa gg BnBn kuku spsp BmBm

Isadora --same ---

kits with 48 hr baldness:s

sax/sax wawa gg Bn Bn kuku Spsp bmbm

The two last alleles within the astrex “suite” (haha) are NOT desirable, I'm thinking. At least not at this time. But both definitely exist. The "curl spotting" causes the curls to be distributed on the body in the way color is distributed on animals with English Spotting. So you can have "patches" of curl in a field of straight fur, and you can have "charlies" where the only curly fur is in areas like ears and whisker bed where other genes do not allow curl to be expressed. We have this in the CPLops. Not good but it has interesting future possibilities - can you imagine a black and white with the black spots curly and the white straight – it would not even be that neat an overlap but what a challenge for the breeder some decades down the road!

As for the balding kit gene - we have to wait and see how the coats on these kits look in a year, and whether they bald with their next molt.

What I think happened in the Astrex is that the original mutation was first found in the bigger Rex rabbits during the 1920's. From there, people

developed the Astrex breed, as a variety of the Rex, and these animals all looked pretty much the way the Astrex does here at my place. Now, the bigger Rex has evolved since then, as breeders increased the body size and the thickness of bone. the modern standard sized Rex rabbits, both here and in the UK, no longer looks the same as it did in the 1930s.

In the meantime, there were other importations that brought Astrex to the USA, both in the 1930's and at later dates. These American Astrex lines appear to have been lost. However they did not disappear without leaving something behind. I believe there probably a lot of crosses made to other Rex varieties to get new colours and to avoid too much inbreeding. Animals of good type for the Rex breed but who exhibited no curl may have been kept for breeding back into standard Rex lines. In those days, knowledge of genetics within the general population was pretty minimal, as DNA was yet to be discovered. Since the desired curly coat genetically a bit more complicated than a simple single recessive, (even though the only genetic work done on it to that point in time, did, unfortunately come to this conclusion), people probably got discouraged and gave up trying for curly rabbits and went back to breeding straight coated Rex. But these recessive curl genes were still lurking within the lines. A lot of these curly genes were continuing to spread through the whole Rex genome and so inevitably got spread in the Mini Rex genome as this breed was developed.

I have made a case here for the linkage of the original “astrex curl suite” with the harelike type of the early rexed rabbit. Now, just because something is linked does not mean it cannot occur separately from the other trait, only that it is harder to get than the two characteristics together. . I think the linkages we see between the curl and the body type may mean that these genes are located on the same chromosome. But I think that full body curl gene is on another chromosome... or else it is at opposite arms of the same chromosomes and so is more likely to break off and recombine with something else (like the normal alleles on the locii for the other genes) during meiosis. So the curly gene suite gradually got broken up again.

And so now, sixty years later, we do see these genes coming together in the right way -just by random chance- to make that curly coat.. But for the Astrex that came to Canada in the late 1940's, time has, in a way, stood still. They were kept relatively pure until I got them, and I have tried to keep them as I found them.

There ALSO has been sufficient time for the linkages between body type and curl genes to be broken repeatedly in the lines of Rex and now Mini Rex that have been evolving in breeders’ hands in the nearly ninety years since the mutations were first discovered. So when the curly coat reappears it may do so on rabbits of all shapes and sizes.

However, here at Golden Spike, this has not happened, since they were not much crossed with anything outside their breed until I got them, and even then, I tried to preserve them as I had found them, because I had made a promise to the old lady I got them from.

I did however use some Astrex to add certain colours to other breeds I was working on. Here, in recent years, despite years “submerged” in several completely different lines with a more “commercial” and compact shape a certain slender elegant hare-like type and the full body curl have tended to re-emerge together. This is only my impression, but it is very strong impression. Or I would not even have bothered advancing this linkage theory at all.

Whether the Astrex will ever recognized as a breed by the ARBA is not known at the present time. I would like to see the original type restored and written into the standard, but I speak only from personal hope