分子标记辅助选择课件

目的基因与标记连锁（交换值为r）
亲本中的标记带型
mM RS
×
F1中的标记带型 F2群体中3种标记带型
RR (1-r)2 0.9025
RS 2r(1-r) 0.095
SS r2 0.0025
当 r=0.05 时 ， 根 据 标 记 基 因 型
mm选择目的基因型RR，选错的
概率约为0.10
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Definitions
第一节 分子标记辅助选择的基本原理
1、概念：
通过基因定位找到与目标基因紧密连锁的分子标记后， 可通过该分子标记间接地对目标性状进行选择。此法称 分子标记辅助选择(Molecular Assistant Selection, MAS )。
MAS 是育种中的一个诱人领域, 将给传统的育种研究 带来革命性的变化。MAS 主要应用在有利基因的转移和 基因的累加等方面。
with a long generation time – Reduce number ofFra Baidu bibliotekgenerations in a backcrossing program by
selecting for recovery of the recurrent parent genome as well as genes of interest from the donor parent
GWS)
– Select for breeding values summed across many markers without estimation of QTL
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(1) selection without test crossing or a progeny test; (2) selection independent of environments; (3) selection without laborious fieldwork or intensive laboratory work; (4) selection at an earlier breeding stage; (5) selection for multiple genes and/or multiple traits; (6) whole genome selection.
– Greatest potential advantage over phenotypic selection for traits with low penetrance or low heritability
May reduce population sizes needed for phenotypic selection
– from a combination of phenotypic value and marker information
4) Marker-assisted backcrossing (MABC) 5) Marker-assisted recurrent selection (MARS) 6) Genomic Selection or Genome-wide Selection (GS or
第十七章 分子标记辅助选择
第一节 分子标记辅助选择的基本原理 第二节 质量性状的标记辅助选择 第三节 数量性状的标记辅助选择 第四节 分子标记辅助选择的挑战与发展策略
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传统的育种主要是根据植株的表现型进行选 择，而环境条件、基因间互作、基因型与环境互作 等多种因素都会影响表型选择效率。
育种者在长期的实践中不断探索运用遗传标记 来提高育种的选择效率与育种预见性。遗传标记包 括形态学标记、细胞学标记、生化标记与分子标记 。
– May permit selection of individual plants
May speed up the breeding process
– May be effective for early generation testing – Selections at the seedling stage can be a great advantage in crops
1) Phenotypic selection (PS)
– based on phenotypic value
2) Marker-based selection (MBS)
– from markers that represent QTL or are linked to QTL
3) Marker-assisted selection (MAS)
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Pyramid genes for a single trait that could not otherwise be distinguished at the phenotypic level
– Accumulating multiple quantitative trait loci (QTL) for disease resistance may provide a higher level of resistance and/or more durable resistance to changes in the pathogen population
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以DNA多态性为基础的分子标记，目前已在作 物遗传图谱构建、重要农艺性状基因的标记定位、 种质资源的遗传多样性分析与品种指纹图谱及纯度 鉴定等方面得到广泛应用，尤其是分子标记辅助选 择（molecular marker-assisted selection ， MAS ）育种更受到人们的重视。
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2、Most suitable for MAS
Useful if conventional screening methods are laborious, costly, or environmentally dependent
– Selections for disease and insect resistance can be made in the absence of the pathogen or pest
Tester M & Langridge Breeding technologies to increase crop production in a changing world. Science,2010,V 327:818-822
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共显性 DNA 标 记的辅 助选择 原理
抗性供体
m
×
R
受体
M S