Characterization of mixed disomic and polysomic inheritance in the octoploid strawberry (Fragaria × ananassa) using AFLP mapping

Abstract

A two-way pseudo-testcross strategy, combined with Single Dose Restriction Fragment (SDRF) marker analysis, was used for genetic mapping in the octoploid cultivated strawberry Fragaria x ananassa (2n = 8 x = 56). Based on a 113 full-sib progeny from a cross between the variety Capitola and the clone CF1116, we generated two parental maps using Amplified Fragment Length Polymorphism (AFLP) markers. Ninety two percent of the markers (727 out of 789) showed ratios corresponding to simplex markers (the majority being SDRF markers), and 8% (62 out of 789) fitted a multiplex ratio. Linkage maps were first established using SDRF markers in coupling phase. The female map comprised 235 markers distributed among 43 co-segregation groups, giving a map size of 1,604 cM. On the male map, 280 markers were assigned to 43 co-segregation groups, yielding a map size of 1,496 cM. Once the co-segregation groups were established, their association was tested using repulsion-phase markers. In total, taking into account associations representing the same linkage groups, 30 linkage groups were detected on the female side and 28 on the male side. On the female map, 68.3% of the pairwise marker linkages were in coupling versus 31.7% in repulsion phase, and the corresponding figures on the male map were 72.2% and 27.8%, respectively. In addition, both groups linked only in the coupling phase and groups linked in the repulsion phase were characterized. The observations suggest that the meiotic behavior of the F. x ananassa genome is neither fully disomic nor fully polysomic, but rather mixed. The genome may not be as completely diploidized as previously assumed.

Comparative Genetic Mapping Points to Different Sex Chromosomes in Sibling Species of Wild Strawberry (Fragaria)

“…chiloensis and F. virginiana are allo-allopolyploids (Bringhurst 1990) with disomic inheritance (2n ¼ 8x ¼ 56) (Ashley et al 2003;Lerceteau-Kö hler et al 2003;Rousseau-Gueutin et al 2008). The two species share a very recent common ancestor (RousseauGueutin et al 2009;Njuguna 2010) and are thought to have diverged only after migration across the Bering Strait to northwestern North America from Asia (Staudt 1999), where F. virginiana dispersed eastward and F. chiloensis southward.…”

A Bayesian Approach for Discriminating Among Alternative Inheritance Hypotheses in Plant Polyploids: The Allotetraploid Origin of Genus Borderea (Dioscoreaceae)

“…However, intermediate classes of genetic inheritance may involve homeologous chromosome pairs (i.e., segmental allopolyploids) (Stebbins 1947) that do not fit with the expected disomic patterns of the heterologous allopolyploids but that could be mistaken to some extent for a randomized polysomic segregation of homologous autopolyploid chromosomes (Stebbins 1950(Stebbins , 1971. Examples of the latter cases have been described in some plant genomes (Wu et al 1992;De Vicente and Arus 1996;Lerceteau-Kö hler et al 2003). Other inheritance types that depart from typical patterns are rare, such as the heterogametic segregation observed in hemisexual polyploid plants .…”

The History Of Genome Mapping In Fragaria Spp.

“…Therefore, all F. × ananassa maps were built on F1 progeny obtained from inter/intraspecific cross pollination (CP) of highly heterozygous cultivars (Haymes et al 1997;Lerceteau-Köhler et al 2003, 2012Rousseau-Gueutin et al 2008;Sargent et al 2009Sargent et al , 2012Goldberg et al 2010;Isobe et al 2012;Gaston et al 2013;van Dijk et al 2014;Mohamed 2014).…”

“…Since more abundant progeny carries a greater number of meiotic recombination events, thus, it determines the resolution and accuracy of the linkage map more precisely (Paterson 1996), larger segregating populations of over 100 individuals were introduced in the study on F. vesca (Koskela et al 2012), F. virginiana and F. chiloensis (Spigler et al 2008Goldberg et al 2010) as well as F. × ananassa (Lerceteau-Köhler et al 2003, 2012Rousseau-Gueutin et al 2008Weebadde et al 2008;Sargent et al 2009Isobe et al 2012;Gaston et al 2013;van Dijk et al 2014). Nevertheless, as some economic factors may limit the progeny number, the bin (selective) mapping appears to be a strategy of choice (Vision et al 2000).…”

“…Scaffolds of the maps were built based on RAPD (Random Amplified Polymorphic DNA) (Davis & Yu 1997;Sugimoto et al 2005), AFLP (Amplified Fragment Length Polymorphism) (Lerceteau-Köhler et al 2003Weebadde et al 2008;Sargent et al 2009), and ISSR (Inter-Simple Sequence Repeat) markers (Cekic et al 2001;Albani et al 2004). However, markers described above have many drawbacks, such as low reliability and insufficient level of polymorphism (RAPD), dominant inheritance (RAPD, AFLP) (Paran & Michelmore 1993), and labourintensive data scoring (ISSR) (Cekic et al 2001).…”