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英语【Hugbook】 (二)not all about Fallow budgerigars  

2014-12-26 19:32:20|  分类: 华乐专版 |  标签: |举报 |字号 订阅

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英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

 

The increase of the mean size in the first generation splits is not significant (0.3cm). However, the increase of the mean size between the Fallows and the second generation splits (hens only) is 1.1cm already. Adult hens from the third generation birds measure on an average 22.4cm, the corresponding cocks 22.8cm. The fourth generation birds measure on average 23.1 cm. The hens 22.3cm and the cocks 23.8cm. A very interesting difference between the sexes we didn't expect.

The observed increase is indicating that we have been moving in the right direction despite the low number of birds we obtained in the fourth generation.

On the graph below we correlated the percentage of "showtype" genes and  the size of the birds. It is obvious that improvement in size can be obtained by the addition of "showtype" genes. It is probably not feasible to achieve a similar effect by selection alone.

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

 The analysis of the size distribution in the third and fourth generation splits revealed interesting points.

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

The variability is high: The difference between the mouse (21.5cm) and the giraffe (24.5cm) is 3cm. Hens are smaller than cocks. Few individuals have the required size of 24 cm. All the other features have to be improved. Another five years plan to think about.

Psychologically it is very difficult to breed split Fallows with Normals for several years in a row because a Fallow breeder would like to breed Fallows. To motivate myself I looked several times a week at the dot found in the right corner of the graph above. The BIG DOT in the right corner was split Fallow and a double factor Australian Pied Lightgreen.

Testmating can be a big thrill.

Is this pudding sweet enough?

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

How do you test your Fallow maybe splits?

By breeding with Fallows indeed. Our testmating procedure is very simple. In a testmating with a Fallow at least three chicks have to be reared and if no Fallows appear then we consider the birds not to be split Fallow. The probability that we miss a carrier of the Fallow gene is reduced to 12% (1 out of 8) with a minimal number of three chicks. If four chicks are bred the probability is down to 6%. The results of a given testmating are already visible immediately after hatching (red eyes!) and the confirmed split Fallow birds can be prepared for the mating with exhibition stock very smoothly without the necessity to rear full clutches of substandard Fallows.

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

Are split Fallows that have been 'washed' through normals more capable of producing quality?

FM: Yes, if the normals have been of exhibition quality. Why? Because in general the Fallows lack most of the exhibition qualities and therefore lack also the genes that carry the information for these qualities. All the missing genetic information required “to construct” an exhibition bird have to be introduced from outside into our Fallows.

A simplified model:
Imagine that only 10 independent recessive genes are required to define a show bird. A perfect show bird has 10 pairs of these recessive genes that are missing in the Fallows. In the first generation all the offspring will be split Fallow. All these birds carry exactly 10 single copies of the recessive genes in split form. The birds will not be improved at all because not a single one of these recessive genes is in double form (to be effective). If you pair these split Fallows together some of the offspring will show small improvements compared to the Fallows and the split Fallows. This is not a surprise as the recessive genes found in the mother and in the father will randomly combine, resulting in Fallows that may carry two copies of one or more of these 10 recessive genes. But one gene in double form is not enough: In this simple model you need ten! These small improvements mentioned above will be minimal if you relate it with your ambitions. Don’t be fooled by the small visible progresses. Genetically the “improved” bird from these matings is not capable of producing good offspring. Most of the “showtype” genes are still missing.
However, if you pair split Fallows (with 10 recessive genes each) from the first generation again to exhibition birds (with a double dose of the recessive genes) then it is obvious that the probability that two corresponding recessive genes will combine in a chick is increased. The required genes (all of them!) are found on both sides of this mating. In contrast, by breeding these splits to Fallows you diminish the small amount of “good genes” you introduced in the parental mating. Mission impossible.

In the case of split Fallows from the first generation, the average number of the required recessive genes that will be distributed to individual germ cells (eggs or spermatozoides) during meiosis is 5 (out of 10) as the total amount of genes is divided by two. The exact distribution of these independent genes is not predictable. In some germ cells you may have 3, 4, 5, 6 or even 7 out of these 10 genes. If you select (by chance) the offspring that received 7 genes from the split Fallow parent (the probability is 12%) you will be surprised by the quality of the offspring. However, the probability is also 12% that only 3 out of 10 recessive genes are found in an individual germ cell. As you have no tools to determine the carrier status of the maybe splits, you are advised to test all your maybe splits not only for the presence of the Fallow gene, but also for the presence of required “show type” genes. This selection can be done visually. In contrast, the carrier status of your split Fallow for “show type” genes cannot be assessed if the birds are crossed back to Fallows or split Fallows.
At this stage you have to face minor disadvantages. You will not breed one hundred Fallows in the first season and you will not know whether the chicks produced are split Fallow or not. But most importantly, you will see for the first time the hidden genetic quality of your split Fallows in the quality distribution of their chicks (BIG-DOT effect). This is theoretically and practically the only way forward with most of the recessive varieties. Please try to estimate the probabilities mentioned above. By using your common sense you will never look back.
Start to pair your split Fallows together when you are happy (happppy with four p's) with the quality (compared to your best exhibition birds). Erstwhile, the Fallows you produce will be Fallows bred from testmatings “only”. The quality of these Fallows will improve slowly with the quality of your splits too. However, this is not quick enough. Go for the splits and mate the splits with your best exhibition birds. This strategy only works when you have enough fertile and fit Fallows for testmating. The time you invest for testmating is not lost. The time to invest for testmating will be six weeks maximally for males and three months for hens. Results can be analyzed immediately after hatching. The speed of your progress will be dramatically increased later on.
This “10 genes only” model is an oversimplification, and it may be anticipated that several hundred of recessive and also dominant genes, that are in several cases also linked, may be responsible for the differences in the type of budgerigars. (In dogs it is estimated that roughly 500 genes are responsible for the characteristic differences between dog breeds.) This model is, however, good enough to illustrate the advantages of the AIDA strategy and this model can also explain why it is so important to breed large amounts of chicks from individual pairs to optimize selection.

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

Are Fallows weaklings and slow developers?

FM: Exhibition budgerigars tend to mature slowly compared to pet type birds. This is not surprising. Today our Fallows do not show delayed maturity. They develop in parallel to their normal siblings. Fallow hens (and also their normal sisters) have nut-brown ceres at six months already. At this age most of them are in breeding condition. Our Fallows seem to develop perfectly normally from the first day on.
However, if we speculate that one of the three confirmed Fallow genes is homologous to the pink-eyed dilution locus p of the mouse [see reference 4], then it is not surprising that certain strains of Fallows show dramatically increased chick mortality as described in the literature. For comparison: In mice more then thirty different mutations of the pink-eyed locus are known. Most of them have problems associated with reproduction (sterility in males, juvenile lethality mild to severe). Similar dramatic observations have been made in mice with mutations of the tyrosinase gene Tyr, another candidate for a Fallow locus within others [reference 5]. Scienific work on red eyes in budgerigars revealed important differences. It was scientifically shown, that the presence of red eyes is not indicating that budgerigars have problems associated with light. They still produce by far enough melanin for protection [reference 7] and they, and this is a very important second point,  behave normally.

On the graph below we plotted the fitness parameters clutch size and number of fletched chicks from 107 pairs that completed 213 rounds. We compared the reproductive success of three different populations. Namely, pairs with one visual Fallow (37 pairs, 59 rounds), pairs with one split Fallow (9 pairs, 22 rounds) and pairs with Normals only (61 pairs, 132 rounds),

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

The variation in all three groups is very high and the significance of the differences can be discussed. The average clutch size in Normals was 5.4 ± 2.7 eggs and the number of chicks fletched was 1.6 ± 2.1. The corresponding data from pairings withs Fallows are 4.8 ± 2.9 and 1.6 ± 2.4. Split Fallows produced an average of 2.7 ± 3.1 chicks from 6.4 ± 3.1 eggs. It is clear that Fallows and split Fallows perform not worse compared to Normals. Such data are psychologically very important and indicate indeed that these Fallows are in good shape and healthy. The presence of the Fallow gene is not detrimental to the reproductive success.
The question about the number of different Fallow genes and their mechanism of action is still not answered yet. Maybe one day the sequencing of the budgerigar genes that are understood to be involved in color production (e.g. Tyrosinase, pink-eyed locus transporter protein e.o.) will give us the answer. These data from the sequencing could provide the Fallow breeders with a tool to assess the carrier status of maybe splits by DNA fingerprinting without testmating. Science Fiction in the Fallow breeding room?

What is happening when a prepotent Fallow cock is mated to a prepotent Fallow hen?

FM: We expect to notice a sensational explosion and we probably have to rebuild our aviary. So far we could avoid such a catastrophe because we don't know how these "prepotent" birds (myths) look like.

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

Can Fallows help to improve other varieties?

FM: Fallow budgerigars are beautiful birds. The exhibition quality is nevertheless still poor. Exhibition budgerigars cannot be improved by using Fallows.
However, Fallows might be useful to solve an enigma that is related to the Yellowface varieties and the Blue allele(s). So far nobody has proven (sorry Mr. Ken Gray) without any doubt that all Yellowfaces (Goldenface, Yellowface mutant 1, Yellowface mutant 2) are multiple alleles of the same Blue locus.
Why should a double factor Yellowface mutant 1 become blue? We prefer the alternative Yellowface model that was first published in the Internet by Peter Bergman of Sydney speculating that the Yellowface mutant 1 birds (Creamfaces) are a composite variety of two different Blue alleles. The Yellowface topic is highly controversial as fanciers of world fame still believe that the Yellowface factor can be carried by birds of the Green series (e.g. the legendary Goldenface Lutinos). Only a few people grasp the “Bergman model” and only a handful think about it. We are currently mating Yellowface mutant 1 budgerigars with Goldenfaces to check whether it is possible to distinguish between the Goldenfaces that are split for the common Blue allele and the Goldenfaces that are split for the “Bergman Blue” allele. These experiments are funny as some of the Goldenfaces are split Danish Pied and some of the Creamfaces are split Clearwing. We are looking forward to find some Yellowface Danish Pied Clearwings popping out, a horror combination for the budgerigar purists. If it is not possible to see differences between these two Goldenface forms on a Normal background it may be possible to see these differences on a Fallow background or on an Albino background. In this case Fallows maybe helpful to introduce a new budgerigar mutation, namely the “Bergman Blue", and to define a new composite variety, namely the Creamface, formerly called Yellowface mutant 1. Can we observe differences in the color distribution (e.g. yellow spillage) or in the color intensity (e.g. head, wing feathers, tail feathers) in the resulting single factor Goldenfaces? Can we observe differences before and after the molt? Can these differences be attributed to the carrier status of the birds?
And so what?
Neither the traditional nor the "Bergman" approach can be excluded by the observation of these differences alone.
And so what?
Based on our observations we suggest that "Goldenface breeders should preferentially breed with the “Bergman Blue" budgerigars, that are identical to the so called "double factor Yellowface mutant 1" budgerigars, to breed nice "yellowfaced single factor Goldenfaces" that do not show yellow spillage".

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

Do you breed Cinnamon Fallows?

FM: Yes, by accident.
German, English, Australian and Japanese Cinnamon Fallows don't look like Cinnamons (body color, markings) and they don't look like Fallows (color gradient, wing color) either. The appearance of Cinnamon Fallows is very similar to "exclusively" colored Inos. Wing markings are very very faint but clearly light brown (cinnamon like). Throat spots are light brown too. Cinnamon Fallows are unique and cannot be confused with Normal Fallows. However, it is not surprising that Cinnamon Fallows have been confused with Lacewings (Cinnamon-Inos). The phenotypes of these color combinations are very similar.

Cinnamon Fallows are very uncommon these days.

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

Do you breed Spangle Fallows?

 

FM: Yes, and we have been surprised by the phenotype of the single factor Spangle Fallows. The markings of these birds are very faint and visible only on the wings. Throat spots are light brown and barely visible due to the presence of the Spangle gene. Tailfeathers are completely white or yellow. The Spangle gene is decreasing the body color of the Fallows even more and resulting birds are amazing. Spangle Fallows in combination with two Violet factors will be very smart birds.

Double factor Spangle Fallows are phenotypically similar to Inos.

The Spangle gene is the most probable candidate gene to be linked to one of the Fallow genes. It is regulating a step in the pigmentation process eventually resulting in a decreased melanin deposition in the growing feathers. Functionally related genes are often found very close on the same chromosome. We are prepared to wait ten years to see Spangle English Fallows popping up! I speculate that the breeders of Fallows with white iris rings have a similar "problem" with the Grey factor.

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

Do you breed Grey Fallows?

FM: We never bred Grey Fallows. I am confident that a relevant part of this question will be answered in Japan in the next future.

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

Can you extrapolate from your Fallow breeding to the breeding of other recessive varieties?

FM: We do not have any expertise with Inos or with Slates but we are breeding Clearwings and Danish Pieds. Clearwings and Danish Pieds are theoretically more difficult to breed to exhibition standard as the color distribution and the color contrast play a decisive role alongside the showtype features. The Fallow is a problem variety because nobody is breeding Fallows. Greys and Greygreens are bred preferentially because people believe that the Grey factor is associated with the label “show quality”. Eventually all the best birds will be Grey factor birds because people breed preferentially with these birds. Fallows will become popular again when more exhibition type Fallows will be available for breeding. Once the Fallow is associated with the label “Best in Show quality”.
We advise bringing a showtype “frame” into recessive varieties by using the AIDA philosophy. But we have no idea how to stabilize the color distribution and how to improve color contrast. To our knowledge the color distribution of pieds in most species (cats?) cannot be predicted and never be fixed by selective breeding. We cannot wisecrack on Clearwings as we have never bred an exhibition Clearwing with clear wings so far. By the way we haven’t seen one either.

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆


References

1. Wachter-Vormann U. (1983). Untersuchungen zum Energie- und Proteinbedarf des Wellensittichs (Melopsittacus Undulatus). Dissertation Universit?t Hohenheim.
2. Budgerigar World. (1999). Issue 207 January: 6.
3. Daniell A. and Murray N.D. (1986). Effects of inbreeding in the budgerigar Melopsittacus undulatus (Aves: Psittacidae). Zoo Biology. 5: 233-238.
4. Orlow S.J. and Brilliant M.H. (1999). The pink-eyed dilution locus controls the biogenesis of melanosomes and levels of melanosomal proteins in the eye. Exp Eye Res. Feb: 68(2): 147-54.
5. Barsh GS. (1996). The genetics of pigmentation: from fancy genes to complex traits. Trends Genet. Aug: 12(8): 299-305.
6. Apanius V D. et al. (1997). The nature of selection on the major histocompatibility complex. Critical Reviews in Immunology 17:179-224.

7. Wilken H. (1998): Mikroskopisch-anatomische Untersuchungen an den Augen "albinotischer" und normalpigmentierter Farbschl?ge des Wellensittichs (Melopsittacus undulatus f. dom.) Hannover, School of Veterinary Medicine, thesis. Awarded with the Erich Aehnelt Memorial Prize.

 


Our virtual expert Frank Molt had to give up (out of the blue) budgie breeding too. Many thanks to Frank as he never stopped to explain us the difference between alleles and genes. He introduced to us the new concepts of yellowface genetics (Pssssst, we still don't understand it), and he was a ferroce enemy of pseudoscientific gubbeldibubble distributed by a bench of fender fixers in the fancy. He and his humour will be missed.   


Further information on Fallow budgerigars

can be found by visiting the links listed in the [Library] or may be obtained from the expert at

英语【Hugbook】  (二)not all about Fallow budgerigars - 虎皮博物馆 - 虎皮博物馆

选自:http://fallowbudgies.schilduil.org/hugbook.html#START

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