Nom du corpus

Corpus Systématique Animale

Titre du document

Karyotypic conservation in the mammalian order monotremata (subclass Prototheria)

Lien vers le document
Éditeur
Springer (journals)
Langue(s) du document
Anglais
Type de document
Research-article
Nom du fichier dans la ressource
Mammiferes_v2b_02476
Auteur(s)
  • Jaclyn M. Wrigley 1
  • Jennifer A. Marshall Graves 1
Affiliation(s)
  • 1) Department of Genetics and Human Variation, La Trobe University, 3083, Bundoora, Australia
Résumé

The order Monotremata, comprising the platypus and two species of echidna (Australian and Nuigini) is the only extant representative of the mammalian subclass Prototheria, which diverged from subclass Theria (marsupials and placental mammals) 150–200 million years ago. The 2n=63?, 64? karyotype (newly described here) of the Nuigini echidna is almost identical in morphology and G-band pattern to that of the Australian echidna, from which it diverged about a million years ago. The karyotype of the platypus (2n=52) has several features in common with those of the echidna species; six pairs of large autosomes, many pairs of small (but not micro-) chromosomes, and a series of small unpaired chromosomes which form a multivalent at meiosis. Comparison of the G-band patterns of platypus and echidna autosomes reveals considerable homology. Chromomycin banding demonstrates GC-rich heterochromatin at the centromeres of many platypus and echidna chromosomes, and at the nucleolar organizing regions; some of this heterochromatin C-bands weakly in platypus (but not echidna) spreads. Late replication banding patterns resemble G-banding patterns and confirm the homologies between the species. Striking heteromorphism between chromosomes of some of the large autosomal pairs can be accounted for in the echidna by differences in amount of chromomycin-bright, late replicating heterochromatin. The sex chromosomes in all three species also bear striking homology, despite the difference in sex determination mechanism between platypus (XX/XY) and the echidna species (X1X1X2X2/X1X2Y). The platypus X and echidna X1 each represent about 5.8% of haploid chromosome length, and are G-band identical. Y chromosomes are similar between species, and are largely homologous to the X (or X1).

Catégories Science-Metrix
  • 1 - health sciences
  • 2 - biomedical research
  • 3 - developmental biology
Catégories INIST
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
  • 4 - vertebres: systeme nerveux et organes des sens
Catégories Scopus
  • 1 - Health Sciences ; 2 - Medicine ; 3 - Genetics(clinical)
  • 1 - Life Sciences ; 2 - Biochemistry, Genetics and Molecular Biology ; 3 - Genetics
Catégories WoS
  • 1 - science ; 2 - genetics & heredity
  • 1 - science ; 2 - biochemistry & molecular biology
Identifiant ISTEX
9D1CAC27913DC3F1D45BF44312B0892CFBEEF204
Revue

Chromosoma

Année de publication
1988
Présence de XML structuré
Non
Version PDF
1.3
Score qualité du texte
10
Sous-corpus
  • Mammiferes
Type de publication
Journal
ark:/67375/1BB-6SR7P1G1-2
Powered by Lodex 9.3.8