A karyological study of Accipitridae (Aves: Falconiformes), with karyotypic descriptions of 16 species new to cytology

Abstract

Karyotypic descriptions are given of 16 species of Accipitridae new to cytology, viz. Torgos tracheliotus. For reasons of comparison the karyotypes are included of 5 species that have been previously studied, viz. Gypaetus barbatus, Haliaeetus albicilla, H. leucocephalus, H. vocifer and Pernis apivorus. All these species share the typical characteristics of the accipitrid karyotype, a moderate diploid number (66-72), the absence of large macrochromosomes, the presence of only 6-12 microchromosomes and a high number of mediumsized to small macrochromosomes. Differences exist in the numbers of biarmed and acrocentric autosomes and in the size and shape of a pair of typical satellited marker chromosomes.The karyological relationships in the Accipitridae are briefly discussed. On the basis of the morphology of the pair of satellited chromosomes (acrocentrics, subtelocentrics or microchromosomes) and the numbers of acrocentric elements nine possible phylogenies are constructed. When compared to conventional phylogenetic trees for the Accipitridae, the following points are remarkable in all possible karyological phylogenies: (1) the position of Pithecophaga is uncertain, it either represents an independent ancient lineage or is related to the Old World vultures; (2) Gypaetus probably is not related to the Old World vultures, it rather evolved from an ancester in common with the booted eagles; (3) genera like Buteo, Geranoaetus and Accipiter may have evolved independently from the booted eagles; and (4) the kites probably do not constitute a natural group.

Evaluation of interspecific DNA content variations and sex identification in Falconiformes and Strigiformes by flow cytometric analysis

“…In particular our study showed interspecies DNA content differences among the studied cases, especially evident in the Falconiformes, confirming data in the literature. In fact, previous studies with cytogenetic analysis (3,4,14) and with static cytometry (19) have revealed substantial difference, in genome constitution, particularly among the species belonging to the Falconiforrnes and, within the Strigiformes, between the two families of Strigidae and T ytonidae. Such variability involves both the chromosome diploid number (2x1) and the nuclear DNA content (pginucleus).…”

First karyotypical description of two American Ciconiiform birds, Mycteria americana (Ciconiidae) and Platalea ajaja (Threskiornithidae) and its significance for the chromosome evolutionary and biological conservation approaches

“…In Accipitridae (Falconiformes), chromosome fusions involving microchromosomes have produced small-and/or medium-sized metacentric chromosomes, with a consequent decrease in the diploid number (De Boer, 1975;De Boer and Sinoo, 1984). In the Ciconiidae, however, microchromosome reduction was not followed by an increase in the number of macrochromosomes, and apparently resulted in loss of microchromosomes (Belterman and De Boer, 1990).…”

cDNA-based gene mapping and GC3 profiling in the soft-shelled turtle suggest a chromosomal size-dependent GC bias shared by sauropsids

“…However, the karyotype of the common ancestor of extant sauropsids is thought to have contained both macrochromosomes and microchromosomes (Burt 2002;Norris et al 2004), although some lineages underwent frequent secondary fusion of microchromosomes resulting in no or few microchromosomes as seen in the reptilian family Crocodylidae and the avian family Falconiformes (Cohen & Gans 1970;De Boer & Sinoo 1984). In contrast, chromosome sizes are relatively uniform and there is no striking bias in inter-chromosomal GC-content in most mammals.…”