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BMC genomics

Construction of a high-density genetic map and mapping of a sex-linked locus for the brown alga Undaria pinnatifida (Phaeophyceae) based on large scale marker development by specific length amplified fragment (SLAF) sequencing.


PMID 26541547

Abstract

Undaria pinnatifida is an important economic brown alga in East Asian countries. However, its genetic and genomic information is very scarce, which hinders further research in this species. A high-density genetic map is a basic tool for fundamental and applied research such as discovery of functional genes and mapping of quantitative trait loci (QTL). In this study the recently developed specific length amplified fragment sequencing (SLAF-seq) technology was employed to construct a high-density genetic linkage map and locate a sex determining locus for U. pinnatifida. A total of 28.06 Gb data including 140.31xa0M pair-end reads was obtained. After linkage analysis 4626 SLAF markers were mapped onto the genetic map. After adding the sex linked simple sequence repeat (SSR) marker [GenBank:AY738602.1], the final genetic map was 1816.28xa0cM long, consisting of 30 linkage groups with an average distance of 0.39xa0cM between adjacent markers. The length of LGs ranged from 20.12 to 106.95xa0cM. A major sex associated QTL was mapped to LG22 within a window starting at 29.01xa0cM and ending at 68.81xa0cM with a total of 68 SLAF markers. The SSR marker and five SLAF markers (Marker6556, 19020, 43089, 60771 and 26359) were identified as tightly sex-linked markers, as indicated by the absence of recombination between them and the sex phenotype. These markers were located at the position of 59.50xa0cM, which was supposed to be the sex determining region. A high-density genetic linkage map was constructed using SLAF-seq technique and F1 gametophyte population for the first time in the economically important brown alga U. pinnatifida. For the first time, a major sex associated QTL suggesting a sex determining region was mapped to a single LG. This map will facilitate the further fundamental and applied research such as QTL mapping and map-based gene clone in U. pinnatifida and provide a reference for studies in other kelp species.