Document Detail

Formation of unreduced megaspores (diplospory) in apomictic dandelions (Taraxacum officinale, s.l.) is controlled by a sex-specific dominant locus.
MedLine Citation:
PMID:  15020437     Owner:  NLM     Status:  MEDLINE    
In apomictic dandelions, Taraxacum officinale, unreduced megaspores are formed via a modified meiotic division (diplospory). The genetic basis of diplospory was investigated in a triploid (3x = 24) mapping population of 61 individuals that segregated approximately 1:1 for diplospory and meiotic reduction. This population was created by crossing a sexual diploid (2x = 16) with a tetraploid diplosporous pollen donor (4x = 32) that was derived from a triploid apomict. Six different inheritance models for diplospory were tested. The segregation ratio and the tight association with specific alleles at the microsatellite loci MSTA53 and MSTA78 strongly suggest that diplospory is controlled by a dominant allele D on a locus, which we have named DIPLOSPOROUS (DIP). Diplosporous plants have a simplex genotype, Ddd or Dddd. MSTA53 and MSTA78 were weakly linked to the 18S-25S rDNA locus. The D-linked allele of MSTA78 was absent in a hypotriploid (2n = 3x - 1) that also lacked one of the satellite chromosomes. Together these results suggest that DIP is located on the satellite chromosome. DIP is female specific, as unreduced gametes are not formed during male meiosis. Furthermore, DIP does not affect parthenogenesis, implying that several independently segregating genes control apomixis in dandelions.
Peter J van Dijk; J M Tanja Bakx-Schotman
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Genetics     Volume:  166     ISSN:  0016-6731     ISO Abbreviation:  Genetics     Publication Date:  2004 Jan 
Date Detail:
Created Date:  2004-03-15     Completed Date:  2004-10-26     Revised Date:  2010-09-21    
Medline Journal Info:
Nlm Unique ID:  0374636     Medline TA:  Genetics     Country:  United States    
Other Details:
Languages:  eng     Pagination:  483-92     Citation Subset:  IM    
Department of Plant Population Biology, Netherlands Institute of Ecology (NIOO-KNAW), Centre for Terrestrial Ecology, Boterhoeksestraat 48, 6666 GA Heteren, The Netherlands.
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MeSH Terms
Chromosome Mapping
Chromosomes, Plant / genetics
Crosses, Genetic
Genes, Dominant
Genes, Plant
Meiosis / genetics
Microsatellite Repeats
Models, Genetic
Reproduction / genetics
Species Specificity
Spores / genetics,  physiology
Taraxacum / genetics*,  physiology*

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