Genetical Research



Lack of detectable genetic recombination on the X chromosome during the parthenogenetic production of female and male aphids


DINAH F.  HALES  a1 c1, ALEX C. C.  WILSON  a2 p1, MATHEW A.  SLOANE  a1, JEAN-CHRISTOPHE  SIMON  a3, JEAN-FRANÇOIS  LEGALLIC  a3 and PAUL  SUNNUCKS  a4
a1 Department of Biological Sciences, Macquarie University, NSW 2109, Australia
a2 Division of Botany and Zoology, The Australian National University, ACT 0200, Australia
a3 UMR Biologie des Organismes et des Populations Appliquée à la Protection des Plantes, INRA, Domain de la Motte BP35327, 35653 Le Rheu Cedex, France
a4 Department of Genetics, La Trobe University, VIC 3083, Australia

Abstract

We used polymorphic microsatellite markers to look for recombination during parthenogenetic oogenesis between the X chromosomes of aphids of the tribe Macrosiphini. We examined the X chromosome because it comprises [similar]25% of the genome and previous cytological observations of chromosome pairing and nucleolar organizer (NOR) heteromorphism suggest recombination, although the same is not true for autosomes. A total of 564 parthenogenetic females of Myzus clones with three distinct reproductive modes (cyclical parthenogenesis, obligate parthenogenesis and obligate parthenogenesis with male production) were genotyped at three informative X-linked loci. Also, parthenogenetically produced males from clones encompassing the full range of male-producing reproductive strategies were genotyped. These included 391 Myzus persicae males that were genotyped at three X-linked loci and 538 males from Sitobion clones that were genotyped at five informative X-linked loci. Our results show no departure from clonality in parthenogenetic generations of aphids of the tribe Macrosiphini: no recombinant genotypes were observed in parthenogenetically produced males or females.

(Received November 19 2001)
(Revised February 15 2002)


Correspondence:
c1 Corresponding author. Tel: +612 9850 8136. Fax: +612 9850 8245. e-mail: dhales@rna.bio.mq.edu.au
p1 Current address: Center for Population Biology, University of California, Davis, CA 95616, USA


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