Microsatellite marker analysis of an anther-derived potato family: skewed segregation and gene–centromere mapping

Abstract

Segregation patterns of polymorphic simple sequence repeat (SSR) primer pairs were investigated in monoploid potato families derived from anther culture. A total of 14 primers developed from the sequences in the database, as well as from a genomic library of potato, was used. Distorted segregation was observed for seven (50%) polymorphic loci among monoploids derived from an interspecific hybrid. Similar distortion was observed for only one of five loci that could be contrasted between the two monoploid families. Segregation distortion was less common in the sexually derived backcross population between the interspecific hybrid and either of its parents. One locus could be putatively linked to a lethal allele because it showed distorted segregation in both monoploid families, a group of 70 heterozygous diploids derived from unreduced gametes through anther culture, and a backcross population. These diploids were used to map the polymorphic SSR markers with respect to the centromeres using half-tetrad analysis. The majority of the SSR loci mapped more than 33 cM from the centromere, suggesting the occurrence of a single crossover per chromosome arm.

Development and genetic mapping of 127 new microsatellite markers in barley

“…This high level of segregation distortion was also observed with RFLPs in the same mapping population and has possibly been caused during the development of the doubledhaploids (Graner et al 1991). Deviations from the expected Mendelian segregation ratios were previously reported for mapping in many different plants based on both co-dominant and dominant marker types (Lyttle 1991;Xu et al 1997;Chani et al 2002;Knox and Ellis 2002). In a study of SSR mapping in maize (Sharopova et al 2002), no evidence was found that the order of markers was influenced by distorted segregation.…”

Genetic Positioning of Centromeres Using Half-Tetrad Analysis in a 4x–2xCross Population of Potato

“…The first was the localization of centromeres on 12 potato chromosomes and the second was the proof of a single crossover per chromosome arm. Previously these two issues for potato chromosome were reported in a few articles (Mendiburu and Peloquin 1979;Douches and Quiros 1987;Bastiaanssen et al 1996;Bastiaanssen 1997;Chani et al 2002). However, they were theoretically proposed or the numbers of loci or chromosomes were limited.…”

Phenotypic characterization and nuclear microsatellite analysis reveal genomic changes and rearrangements underlying androgenesis in tetraploid potatoes (Solanum tuberosum L.)

“…Since both the androgenic (di)haploids represent the gametes directly and SSR is a codominant marker, it is possible to explain the reasons for such high polymorphism based on recombination vis-à-vis crossover events. The microsatellite locus POTM1-2 representing a dinucleotide repeat (AT) has been mapped at the farthest (42.65 cM) from the centromere (Chani et al 2002) amongst the other loci characterized in this study, for which gene-centromere map positions are available. This provides a strong basis for high polymorphism detected at this locus because the probability of a crossover in meiosis increases with distance from the centromere (Chani et al 2000), accepting the hypothesis of a single crossover per chromosome arm in potato microspores (Bastiaanssen et al 1996).…”

“…In this study, the androgenic competence of tetraploid potatoes was also assessed, and the anther-derived plants obtained were characterized for ploidy level, chromosome number and nuclear DNA variation. DNA markers have been extensively used for assessing the genetic variation and for determining the genetic composition of anther-derived plants in potato (Birhman et al 1994;Rivard et al 1994;Veilleux et al 1995;Chani et al 2000Chani et al , 2002. All these studies were, however, confined to the genetic analyses of monoploid and/or diploid anther-derived plants, which originated from diploid S. chacoense or S. phureja anther donors, or their interspecific hybrids.…”

“…Microsatellites, also termed as simple sequence repeats (SSRs), have been used to distinguish homozygous doubled monoploids from heterozygous diploid plants in a monoploid anther-derived population originated from an interspecific diploid hybrid between S. chacoense and S. phureja (Veilleux et al 1995;Chani et al 2000Chani et al , 2002. They offer the same discriminatory potential as RFLPs because both alleles of a heterozygote can be detected (Veilleux et al 1995).…”