Malcolm A. Ferguson-Smith

Patricia C. M. O’Brien8
Vladimir A. Trifonov7
Patricia CM O'Brien4
8Patricia C. M. O’Brien
7Vladimir A. Trifonov
4Patricia CM O'Brien
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BACKGROUND Gymnotus (Gymnotidae, Gymnotiformes) is the Neotropical electric fish genus with the largest geographic distribution and the largest number of species, 33 of which have been validated. The diploid number varies from 2n = 39-40 to 2n = 54. Recently we studied the karyotype of morphologically indistinguishable samples from five populations of G.(More)
BACKGROUND Sex-determining systems have evolved independently in vertebrates. Placental mammals and marsupials have an XY system, birds have a ZW system. Reptiles and amphibians have different systems, including temperature-dependent sex determination, and XY and ZW systems that differ in origin from birds and placental mammals. Monotremes diverged early in(More)
BACKGROUND The evolution of genomic imprinting, the parental-origin specific expression of genes, is the subject of much debate. There are several theories to account for how the mechanism evolved including the hypothesis that it was driven by the evolution of X-inactivation, or that it arose from an ancestrally imprinted chromosome. RESULTS Here we(More)
In contrast to mammals, birds exhibit a slow rate of chromosomal evolution. It is not clear whether high chromosome conservation is an evolutionary novelty of birds or was inherited from an earlier avian ancestor. The evolutionary conservatism of macrochromosomes between birds and turtles supports the latter possibility; however, the rate of chromosomal(More)
Most eukaryotic species represent stable karyotypes with a particular diploid number. B chromosomes are additional to standard karyotypes and may vary in size, number and morphology even between cells of the same individual. For many years it was generally believed that B chromosomes found in some plant, animal and fungi species lacked active genes.(More)
  • Jesús Aguirre-Hernández, Bruce S Milne, Chris Queen, Patricia CM O'Brien, Tess Hoather, Sean Haugland +3 others
  • 2009
BACKGROUND In dogs in the western world neoplasia constitutes the most frequently diagnosed cause of death. Although there appear to be similarities between canine and human cancers, rather little is known about the cytogenetic and molecular alterations in canine tumours. Different dog breeds are susceptible to different types of cancer, but the genetic(More)
Gekkotan lizards are a highly specious (∼1600 described species) clade of squamate lizards with nearly cosmopolitan distribution in warmer areas. The clade is primarily nocturnal and forms an ecologically dominant part of the world nocturnal herpetofauna. However, molecular cytogenetic methods to study the evolution of karyotypes have not been widely(More)
Avian genome organisation is characterised, in part, by a set of microchromosomes that are unusually small in size and unusually large in number. Although containing about a quarter of the genome, they contain around half the genes and three quarters of the total chromosome number. Nonetheless, they continue to belie analysis by cytogenetic means.(More)
Turdus rufiventris and Turdus albicollis, two songbirds belonging to the family Turdidae (Aves, Passeriformes) were studied by C-banding, 18S rDNA, as well as the use of whole chromosome probes derived from Gallus gallus (GGA) and Leucopternis albicollis (LAL). They showed very similar karyotypes, with 2n = 78 and the same pattern of distribution of(More)
BACKGROUND Flying lemurs or Colugos (order Dermoptera) represent an ancient mammalian lineage that contains only two extant species. Although molecular evidence strongly supports that the orders Dermoptera, Scandentia, Lagomorpha, Rodentia and Primates form a superordinal clade called Supraprimates (or Euarchontoglires), the phylogenetic placement of(More)