讲座信息
| 06月 26th, 2007 | by zhongtiannongmin |
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zhiwu博士将于近期回国探亲，他将受邀在中国农大，中国农科院和华中农业大学等地作学术报告。
house和他的科学研究一样有创意！让我留恋往返！希望从事相关研究的老师同学有机会能积极参与探讨！
Mystery of Heterosis
Although heterosis has been widely used and improved the animal
and plant production in the world, its genetic base was still not
well understand. Consequently, the potential of heterosis has not
been fully utilized. There are two obstacles preventing heterosis
from being understood. The first is that the heterosis is not an
observation that can be directly measured on single individual. It
was usually presented by the difference of cross from the average
of parents. As a consequence, a 125% of residual variance was mixed
to the total variation of heterosis. The second obstacle is that
heterosis is caused by non additive genetic effect including
dominance and epitasis. Although many efforts have been done to
overcome the second obstacle, the picture on heterosis is still not
very clear as the first obstacle defeat the efforts on solving the
second obstacle. A better estimate of heterosis was derived which
contains less residual variation. It was approved by simulation
that the estimate has higher power than the conventional
presentation for detecting QTL that control heterosis. A real
example from “IF2” population in maize was employed to illustrate
the enhancement of using the heterosis estimate for exploring the
genetic basis of heterosis and predicting performances for breeding
superior hybrid.
Positives in Genotype‐Phenotype Association
Analyses
associations have been rapidly expanded for many economic important
traits and human diseases due the cost‐effective genotyping
technologies.
As quite amount of reports were questionable for replication,
reducing false positives in the association analysis is becoming
crucial to restore creditability in the science community. The
genotype‐phenotype association has been dissected to the
association by physical linkage,
which is more replicable, and many other associations that cause
false positives. A variety of genetic and statistical models,
including mixed model were presented to decompose the association
components. The considerations for model selection were discussed
to pursue the goal of maximizing statistical power and minimizing
false positive imultaneously. Three free software packages (SAS
macro LORG, MTDFREML and TASSEL) were described for using the most
advanced genetic and statistical model with the minimum effort from
researchers. Finally,
two real examples (one in animal and one in plant) were given to
illustrate one of the most difficult processes of QTL mapping and
show the advantage of collaboration to discover QTL.
上午在农科院畜牧所还有一个纯统计分析方面的讲座，有兴趣的也可以去听听！