title: Ordered tandem arrangement of chromosomes in the sperm heads of monotreme mammals.
abstract: A very old unanswered question in classical cytology is whether chromosomes are arranged randomly in sperm or whether they occupy specific positions. Even with modern methods of chromosome painting, it is difficult to resolve this question for the very condensed and almost spherical sperm head of most mammals. We have taken advantage of the unusual fibrillar sperm head of monotreme mammals (echidna and platypus) to examine the position of chromosome landmarks in a two-dimensional array. We used fluorescence and radioactive in situ hybridization to telomeric, rDNA, and unique sequences to show that chromosomes are arranged tandemly and in a defined order in the sperm nucleus.
authors.affiliation: School of Genetics and Human Variation, La Trobe University, Bundoora, Victoria, Australia.
authors.forename: J M
authors.initials: JM
authors.lastname: Watson
authors.forename: J
authors.initials: J
authors.lastname: Meyne
authors.forename: J A
authors.initials: JA
authors.lastname: Graves
mesh_terms: D000818:Animals; D002875:Chromosomes / Q000648:ultrastructure*; D015342:DNA Probes; D004275:DNA, Ribosomal / Q000032:analysis / Q000737:chemistry; D006570:Heterochromatin / Q000648:ultrastructure; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D010987:Platypus; D012867:Skin / Q000648:ultrastructure; D013045:Species Specificity; D013077:Sperm Head / Q000648:ultrastructure*; D004442:Tachyglossidae; D013737:Testis / Q000166:cytology; D014982:Xenopus laevis
chemical_list: D015342:DNA Probes; D004275:DNA, Ribosomal; D006570:Heterochromatin