| ORIGINAL BOOK REVIEW by Dr. Rainer R. Erhardt "Well, there is help on the horizon and anyone seriously interested in color genetics should take a look at Linda Rubin's book: COCKATIEL GENETICS MADE EASY! Though this book is primarily directed to breeders of cockatiel mutations, there is enough information in this little volume to teach anyone the secrets of dealing with recessive, sex-linked, and dominant mutations..." ACBM, Vol. 65, No.12 CLICK TO READ THE REST OF THE REVIEW! 112 pages, 15 chapters, glossary & more! |
Copyright 2006 Linda S. Rubin
| Multiple Bird Households by Linda S. Rubin |
| Series by Linda S. Rubin |
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| Normal Grey & Lutino Chicks plus Pearl Splits Copyright © 2003 LINDA S. RUBIN CF Genetics Consultant/Panel Judge www.CockatielsPlusParrots.com From "My Mailbox" Q. Our pair of cockatiels hatched out three chicks. The parents are Normal Grey and Grey with pearling. They had two Normal Grey chicks and the third chick is white with a slight yellow tint on some areas of its body, yellow in the tail and head, orange cheek patches, pink eyes, feet, and beak. We are fairly certain the mother is a Normal Grey split to Pearl; we don’ t know the background of the father who appears to be a Normal Grey. This was the pair’s first successful clutch out of 5 attempts; 3 out of 4 eggs hatched in the last round. If the parents have another clutch in the future, what is the chance of this happening again? Thanks so much. A. Congratulations on your new chicks! The third chick you describe as a “white” cockatiel is known as a Lutino mutation, which is sex- linked in its mode of inheritance. The Lutino is one of the earliest color mutations to appear in cockatiels. Lutinos retain all carotenoid (e.g., yellow and orange) pigments but lose all melanin (e.g., grey) pigment. Some Lutinos are mostly white with some yellow on the face and tail; others may be suffused with a yellow tint, and still others are selectively bred for a deep yellow appearance. All Lutinos have red eyes, pink feet and beak. Because your adult pair produced one visual Lutino, it indicates that the cock is split or heterozygous to Lutino. The Lutino is a sex-linked recessive mutation, which means your adult cock is carrying the sex- linked gene for Lutino in the recessive state. Because your pair produced only Normal Grey colored offspring rather than visual Pearls, we have to assume that it is your adult hen that is the Pearl mutation of this pair (if indeed she is a Pearl mutation). If the hen is Pearl, she will pass on the gene for the Pearl mutation to her male progeny. This means that all her male offspring will always be split to Pearl. We know that the mother has to be the Pearl mutation in this particular pair, because if the father were Pearl, then visual Pearl female progeny would have been produced in the first generation. The percentages now work out correctly. Therefore: Normal Grey/Lutino cock paired to a Pearl hen = XL X | XP Y --------------------------------------- XL XP XL Y X XP X Y 25% Normal Grey split to Lutino and Pearl males 25% Normal Grey split to Pearl males 25% Lutino females 25% Normal Grey females As demonstrated here, the ratio of one in four per clutch will be a visual Lutino hen. However, these figures are based on every 100 chicks produced over the lifetime of the pair, so in reality there will be times when you may produce a preponderance of Lutino hens, and then may have none for several more clutches (or vice-versa). It will all even out eventually so that if the pair were to produce 100 chicks over the years, 25 of them would be Lutino daughters. One point I would like to comment upon is that your adult hen cannot be split to Pearl. She is either Normal Grey OR Pearl; she cannot be both it's an either/or situation. This point will be clarified after we discuss the phenotypes or physical appearances of Normal Greys and Pearl mutations and how they differ in hens. The adult Normal Grey hen has some yellow spots or splashes on the face that would be limited to the forehead, near the eyes, and under the chin, with yellow barring on the underside of tail feathers and yellow spotting on the underside of flight feathers. Both genders carry the usual white wing bar and orange cheek patch, although the latter will be duller in intensity in the hen. In contrast, a sex-linked Pearl mutation hen is marked with individual pearl lacings down the back. These Pearl lacings may be either yellow, or white, or both yellow and white; they can vary in their extensiveness from lightly marked to heavier marked birds where the lacings extend from the back of the head, all the way down the back, and are more concentrated on the shoulders. In better-marked birds, the pearl lacings are very clear and distinct. However, in those Pearls that are lightly marked, the pearl lacings will appear much smaller and more sporadic. (Refer to the article on Pearls in this section of the Color Mutation Articles. Keep in mind, however, that as a sex-linked mutation, Pearl hens are either visual Pearls, or they are not Pearl at all. In other words, hens can never be split to Pearl. The reason why a Pearl hen cannot be split to Pearl is because a hen carries only one X sex chromosome. In order to be heterozygous or “split” like a male, the hen would need a second X chromosome to mask the X chromosome carrying the Pearl gene. Instead, a hen has a smaller Y sex chromosome paired with her X sex chromosome (XY = hen). Because the Y sex chromosome is not well formed and is much smaller, it cannot mask the X chromosome carrying the Pearl color mutation. Therefore, as a result, any sex- linked color genes located on the hen's X chromosome will be visual. For example = X Y = Normal Grey hen X X = Normal Grey male XP Y = Pearl hen XP X = Normal Grey split Pearl male XP XP = Pearl male If, by chance your hen is not Pearl, but rather, a Normal Grey with sporadic white flecking (that is considered a small fault in the color category of the show standard), then the charting would change to the following: Normal Grey/Lutino cock paired to a Normal Grey hen XL X | X Y ----------------------------------- XL X XL Y X X X Y 25% Normal Grey split to Lutino cocks 25% Normal Grey cocks 25% Lutino hens 25% Normal Grey hens Always rest your cockatiels after laying several rounds of eggs because it depletes the calcium stores and energy reserves, with severe consequences. Egg-laying is a stressful event and ideally, pairs should be rested a minimum of six months after their second or third consecutive clutch. |
| c. 2005 Linda S, Rubin c.2007 Herschel & Elsie Burgin |
| NORMAL GREY & LUTINO CHICKS PLUS PEARL SPLITS Copyright © 2003 Linda S. Rubin All Rights Reserved |
Copyright 2006 Linda S. Rubin