遺傳改造作物的基因滲入進入到野生親緣種的可能性定量分析-隨機式模型的探討

Quantitative analysis of the likelihood of gene introgression from genetically modified crops into wild relatives-A study of stochastic model

楊水木(Shui-Mu Yang)

指導教授 ： 彭雲明

國立臺灣大學/生物資源暨農學院/農藝學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00989

摘要

近年來,隨著遺傳改造作物的日漸增加,引發生物學家考慮以合適的數量模型為基礎,去評估GM作物基因滲入到相關野生親緣種的可能性。本論文提供一般性的模式,並且應用在GM作物上,用來描述雜交種族群與野生親緣種族群的競爭。
考慮兩個分別來自芸薹屬和棉屬的物種,用電腦模擬的方法去探討隨機式模型,即在自然環境之下雜交種與野生親緣種之間的競爭。我們發現當雜交率正常及雜交種是可生育的,則結果傾向於基因轉殖進入到野生種族群;當基因滲入需要一個自發性多倍體的產生(即雜交種是不可生育的),則基因滲入的可能性變得很小。這個結果與決定式模型的結果相同。
相異之處為決定式模型的起始點決定其最後之穩定平衡點,而隨機式模型的起始點只能決定一個分布,這個分布有三種可能: 1)野生種占優勢[A];2)雜交種獨占[D]; 3)野生種與雜交種兩者均滅絕[O]。

關鍵字

決定式模型 ； 平衡點 ； 遺傳改造作物 ； 隨機式模型

並列摘要

Recently, due to the gradual increase of cultivation area of genetically modified crops, biologists turn to consider suitable mathematical models as a basis to evaluate the likelihood of gene introgression from genetically modified crops into wild relatives. This thesis provides a general model and apply it in GM crops to describe the competition between hybrid population and wild relative population.

Consider two species from the genera Brassica and the genera Gossypium, respectively. We use a simulation method to study the stochastic model for modelling the competition between hybrid population and wild relative population in a natural environment. We find that when hybridization rates are moderate and hybrids are fertile, the results are likely to lead to escape of transgenes into wild population. When gene introgression requires the spontaneous development of a polyploid, the likelihood of gene introgression is very low.This result coincide with that obtained from the deterministic model derived by Thompson et al.

For the stochastic model, an initial value might end in one of the three possible outcomes rather than a destined equilibrium as characterized by a deterministic model.

並列關鍵字

deterministic model ； genetically modified crops ； stochastic model ； equilibrium point

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