Assuntos
Perissodáctilos/genética , Elementos Nucleotídeos Curtos e Dispersos , Animais , Sequência de Bases , DNA/genética , Primers do DNA/genética , Equidae/genética , Genoma , Cavalos/genética , Humanos , Dados de Sequência Molecular , Filogenia , Homologia de Sequência de Aminoácidos , Especificidade da EspécieRESUMO
Wild-born orang utans held in zoos do not have their geographic origins defined, which has complicated comparisons of the two subspecies of orang utans (Bornean orang utans, Pongo pygmaeus pygmaeus, and Sumatran orang utans, P. pygmaeus abelii). The resulting confusion concerning the subspecies identity of individual orang utans and a larger controversy over the desirability of utilizing subspecies designations in orang utan breeding programs has focused attention on the need for a phylogenetic analysis of the species and an examination of the appropriateness of the subspecific designations. Previous studies have suggested that an inversion in the second chromosome pair (PPY2) is a diagnostic subspecies marker and that mitochondrial DNA (mtDNA) and nuclear genetic markers may also be used to identify the subspecies origin of individual orang utans. In an effort to assist zoological parks in examining the question of genetic divergence of orang utan subspecies, we have studied the chromosomes of 144 orang utans, including 58 wild-born individuals. To gain insight into phylogenetic divisions of these apes, mtDNA restriction cleavage site variation has been investigated in 14 individuals whose karyotypic status was known. These investigations have confirmed the existence of two phylogenetic lineages of orang utans based on mtDNA cleavage patterns and demonstrated that these lineages correspond with the two populations characterized by the G-banded morphology of the second pair of chromosomes. The two orang utan phylogenetic units comprise individuals that generally conform to the recognized allopatric, morphological subspecies. Based on current knowledge, the view that the named orangutan subspecies each constitute a distinct phylogenetic lineage more consistent with species-level divergence is supported.
Assuntos
Cromossomos , DNA Mitocondrial/genética , Polimorfismo Genético , Pongo pygmaeus/genética , Animais , Células Cultivadas , Enzimas de Restrição do DNA , Cariotipagem/veterinária , Filogenia , Pongo pygmaeus/classificaçãoRESUMO
Chromosomal studies of Tibetan wild ass, Equus kiang holdereri are reported for the first time. A Robertsonian polymorphism resulting in diploid numbers of 2n = 51 and 2n = 52 was identified. This polymorphism involves the same elements that participate in the polymorphic Robertsonian rearrangement producing diploid numbers of 54-56 in E. hemionus kulan and E. hemionus onager. Comparison of mitochondrial DNA restriction fragment patterns among three unrelated kiang individuals and between kiangs and a Transcaspian kulan, E. hemionus kulan, indicates an approximately 1% nucleotide sequence divergence of mitochondrial DNAs between the two taxa. The chromosomal divergence between E. hemionus and E. kiang probably originated less than 500,000 years ago. Studies of additional Asiatic wild ass taxa are indicated in order to gain further insights into the speciation and systematics of this threatened group of mammals.
Assuntos
Perissodáctilos/genética , Animais , Evolução Biológica , Cromossomos , DNA Mitocondrial/genética , Diploide , Feminino , Variação Genética , Masculino , Perissodáctilos/classificação , Polimorfismo GenéticoRESUMO
Whereas mules are normally considered sterile, reports of fertile female mules persist. However, none subjected to cytogenetical and blood typing analyses could be confirmed as having indeed been mules that transmitted maternal markers to their alleged offspring. Reported here is the case of a cytogenetically verified female mule whose alleged male foal qualifies as offspring by a male donkey. The male foal is karyotypically a mule.
