The crested mutant in zebra finches was shown statistically to be an autosomal codominant lethal. Homozygous crests likely die as embryos. Even the heterozygous crests were deficient in numbers, allowing the conclusion that heterozygous crest in zebra finches is also detrimental (subvital), or it has reduced penetrance.

The wild-type zebra finch, Taeniopygia guttata (previously Poephila guttata), (Figures 1 and 2) has a smooth cap of feathers from the beak over the top of the head (Figure 3). Crested zebra finches often have a flattish, or somewhat raised rosette, nearly a centimeter in diameter on the top of the head (Figure 4). Sometimes the crest is reduced in size and the feathers stand more erect, so that the crest does not resemble a complete rosette (Figure 5). Thus, there can be some variable expressivity.

The zebra finch's crested mutant gene is a dominant gene (Zann, 1996). Any outcross of a crested zebra finch to a normal yields some crested offspring. And crested offspring have not resulted from non-crested parents. However, the mutant could be a codominant lethal (Miller, 1996 and 1997), as in canaries or certain breeds of domestic ducks (general knowledge with canary and duck breeders). When crested zebra finches became available, the question naturally arose as to whether inheritance in crested zebra finches was like the inheritance in the crested canary and crested ducks.

The senior author has kept a few breeding pairs of the zebra finch at his home since 1985. Most of the original non-crested stock came from Garrie Landry, Louisiana (Miller, 1978). The crested zebra finches came from The Ark, a pet store in Ames, Iowa, in the year 1999.

Genetics & Evolution Journal, Zebra Finches, Homozygous Crests, Heterozygous Crests, Breeding Pairs, Testcrosses Information, North American Birds, Brain Hernia, Budgerigar Genes, Mendelian Recessive Inheritance, Homozygous Mutant Birds, Heterozygous Mutant Birds.