Chromosome banding pattern conservatism in birds and nonhomology of chromosome banding patterns between birds, turtles, snakes and amphibians

Abstract

The G-banded karyotypes of 4 species of birds representing the orders Galliformes, Columbiformes and Musophagiformes were compared. Banding pattern homology between orders was limited t 5o 5 major chromosome arms and the Z chromosome. Even in these major chromosome arms pericentric and paracentric inversions produced alteration of the banding pattern sequences. Addition of constitutive heterochromatin was responsible for changes in banding patterns in the Z chromosome. The chromosome banding patterns of an emydid turtle, Terrepene carolina, 5 species of boid snakes of the genera Liasis, Acrantophis, and Sanzinia and the African clawed-frog. Xenopus muelleri, were also compared to the bird chromosome banding patterns. No homology was observed between any of these major groups: bird, snake, turtle, amphibian. However, intergroup homology was apparent. - The data obtained do not support reports of broad interordinal direct homology of the macrochromosomes of birds and refutes the idea of a primitive bird karyotype with 3 pairs of "Agroup' chromosomes and 3 pairs of "B group' chromosomes. - The major mechanisms responsible for chromosome evolution in birds appear to be centric and tandem fusions, paracentric and pericentric inversions, and addition or deletion of heterochromatin.

Conservation of chromosome 1 in turtles over 66 million years

“…Many pleurodires have substantially lower chromosome numbers (Ayres et al, 1969;Bull and Legler, 1980). The localization of euchromatin in subtelomeric and pericentromeric regions in the macrochromosomes is also evident in previous reports of G-banded karyotypes from a variety of turtle species (Stock and Mengden, 1975;Bickham, 1980;Bull and Legler, 1980;Carr et al, 1981;Haiduk and Bickham, 1982; and contrasts with the pattern for humans and other mammals where many chromosomes contain pericentromeric heterochromatin. The T. scripta genome has a DNA content similar to that of humans (Mirsky and Ris, 1949;Atkin et al, 1965).…”

A comparative study of the chromosomes in 5 species of birds from the genus Aratinga (Psittaciformes: Aves).

“…The banding patterns of bird chromosomes have revealed a surprising similari ty for the three or four largest chromosomes (Takagi and Sasaki 1974, Stock et al 1974, Stock and Mengden 1975, Ryttman et al 1979. This fact is obvious for the largest chromosomes in Aratinga.…”

Differential staining of cultured bone marrow cell chromosomes of Rana pipiens.

“…G-banding of certain select chromosomes has been reported for chromosomes of cultured cells of Xenopus muelleri (Stock and Mengden 1975). Extensive work on C-banded chromosomes has been reported for numerous species of Anura.…”