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

TY - JOUR

T1 - Formation of unreduced megaspores (Diplospory) in apomictic Dandelions (Taraxacum officinale, s.l.) is controlled by a sex-specific dominant locus

AU - van Dijk, P.J.

AU - Bakx-Schotman, J.M.T.

N1 - Reporting year: 2004 Metis note: 3226; CTE; PVP ; TE file:///L:/Endnotedatabases/NIOOPUB/pdfs/Pdfs2004/VanDijk_ea_3226.pdf

PY - 2004

Y1 - 2004

N2 - 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.

AB - 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.

KW - NIOO/CTE/PVP

U2 - 10.1534/genetics.166.1.483

DO - 10.1534/genetics.166.1.483

M3 - Article

SN - 0016-6731

VL - 166

SP - 483

EP - 492

JO - Genetics

JF - Genetics

IS - 1

ER -