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Formation of unreduced megaspores (Diplospory) in apomictic Dandelions (Taraxacum officinale, s.l.) is controlled by a sex-specific dominant locus

Dijk van, P.J. and Bakx-Schotman, J.M.T. (2004) Formation of unreduced megaspores (Diplospory) in apomictic Dandelions (Taraxacum officinale, s.l.) is controlled by a sex-specific dominant locus. Genetics, 166, 483-492. ISSN 0016-6731.

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Official URL: http://dx.doi.org/10.1534/genetics.166.1.483

Abstract

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 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.

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:11597
Deposited On:23 Nov 2011 01:00
Last Modified:15 Jan 2014 09:24

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