Construction of a high-density composite map and comparative mapping of segregation distortion regions in barley

Abstract

Segregation distortion can negatively impact on gains expected using selection. In order to increase our understanding of genetic factors that may influence the extent and direction of segregation distortion, segregation distortion analyses were conducted in four different doubled haploid (DH) populations. A high-density composite map of barley was then constructed by integrating information from the four populations. The composite map contained 2,111 unique loci, comprising RFLP, SSR and DArT markers and spanned 1,136 cM. In the four populations investigated, the proportion of markers with segregation distortion ranged from 15 to 38%, depending on the population. The highest distortion was observed in populations derived by the microspore culture technique. Distorted loci tended to be clustered, which allowed definition of segregation distortion regions (SDRs). A total of 14 SDRs were identified in the 4 populations. Using the high-density composite map, several SDRs were shown to have consistent map locations in two or more populations; one SDR on chromosome 1H was present in all four populations. The analysis of haplotypes underlying seven SDRs indicated that in three cases the under-represented haplotypes were common across populations, but for four SDRs the under-represented haplotypes varied across populations. Six of the seven centromeric regions harboured SDRs suggesting that genetic processes related to position near a centromere caused the segregation distortion in these SDRs. Other SDRs were most likely due to the methods used to produce the DH populations. The association of the SDRs identified in this study and some of the genes involved in the process of haploid production described in other studies were compared. The composite map constructed in this study provides an additional resource for the barley community via increased genome coverage and the provision of additional marker options. It has also enabled further insights into mechanisms that underpin segregation distortion.

Constructing a new integrated genetic linkage map and mapping quantitative trait loci for vegetative mycelium growth rate in Lentinula edodes

“…The mapped skewed loci appeared to locate together as segregation distortion regions in the genetic map, as previously reported in L. edodes (Terashima et al 2002), P. pulmonarius (Okuda et al 2009) and P. eryngii (Okuda et al 2012). The cluster distribution of skewed loci seemed to indicate that the segregation distortion of markers is most likely caused by genetic factors rather than statistical bias (Li et al 2010).…”

Development of DNA Markers Linked to Double-Flower and Hortensia Traits in <i>Hydrangea macrophylla</i> (Thunb.) Ser.

“…The reason for the skewed segregation in our study is unclear. Segregation distortion is a common phenomenon in many plants and is recognized as a potentially powerful evolutionary force (Li et al, 2010;Li et al, 2015); however, its underlying mechanism is not understood (Cai et al, 2015). Suggested causes include aneuploidy, chromosomal translocation, competition among gametes, and the inheritance of alleles affecting the viability of the zygote, embryo, or seedling (Lashermes et al, 2001).…”

Diversifying Sunflower Germplasm by Integration and Mapping of a Novel Male Fertility Restoration Gene

“…Segregation distortion, also called "meiotic drive," may be caused by genetic elements, including gametic selection (pollen tube competition, lethal pollen, and preferential fertilization), zygotic selection, interspecific sterility genes (S), and chromosome translocation (Lyttle 1991;Kumar et al 2007;Gutiérrez et al 2010;Liu et al 2010). It has been suggested that meiotic drive elements are highly important for the evolution of recombination and sexual reproduction (Hurst and Werren 2001;Jaenike 2001;Li et al 2010).…”

“…Segregation distortion, also called "meiotic drive," may be caused by genetic elements, including gametic selection (pollen tube competition, lethal pollen, and preferential fertilization), zygotic selection, interspecific sterility genes (S), and chromosome translocation (Lyttle 1991;Kumar et al 2007;Gutiérrez et al 2010;Liu et al 2010). It has been suggested that meiotic drive elements are highly important for the evolution of recombination and sexual reproduction (Hurst and Werren 2001;Jaenike 2001;Li et al 2010).Segregation distortion has been reported for sunflower populations derived from the interspecific crosses involving wild species in the mapping of a downy mildew resistance gene on LG 1, Pl ARG , which originated from H. argophyllus Torrey and Gray (Dußle et al 2004;Wieckhorst et al 2010). Significant segregation distortion of the codominant markers closely linked to the Pl ARG gene was observed in the F 2 Figure 4 Representative results of the markers amplified by the ORS433 primer pair among the four bulks and the individuals constituting each bulk, respectively, on a nondenaturing polyacrylamide gel.…”