摘要
本研究先论证了"隐性有害"基因纯合致使自交衰退的本质是有利遗传物质缺失,定义了有利遗传物质、有害遗传物质、偏中性遗传物质。提出了物质淘汰定律和遗传物质优胜定律,遗传物质淘汰定律认为:一般来说,在一定的环境标准下,越有害的遗传物质淘汰可能性越高,越有利的遗传物质淘汰可能性越低,越有害的遗传物质淘汰速度越快的可能性越高。遗传物质优胜定律认为:一般来说,在一定的环境标准下,越有害的遗传物质遗传给后代或者扩散到群体的机会越少,越有利的遗传物质遗传给后代或者扩散到群体的机会越多,越有利的遗传物质扩散到群体速度越快的可能性越高。基于遗传物质淘汰定律、遗传物质优胜定律及生物体内除害系统推导出遗传物质组成定理,遗传物质组成定理为:在一个长期稳定的外在环境下,在此外在环境下长期进化或者生存的生物,以此外在环境和生物体内环境为标准,其体内遗传物质组成成份为:有利遗传物质占大多数或者绝大多数,偏中性遗传物质占少数或者极少数,有害遗传物质能够存在的概率极小,即使存在有害遗传物质也只有一个或者少数几个。基于遗传物质组成定理和异交生物同源染色体上遗传物质存在差异的基础上提出异交生物自交衰退新假说,该假说认为:在长期稳定的一定环境下,一般来说,由于异交生物同源染色体上遗传物质存在差异,存在差异的遗传物质或者说不同时存在于同源染色体的遗传物质在自交后有不存在于自交子代的可能,造成自交子代相对于亲本有利遗传物质缺失,导致出现2种结果:第一种有利遗传物质缺失不影响其它遗传物质致使有利遗传物质相对应的有利性状消失;第二种由于有利遗传物质缺失导致一些相关的有利遗传物质部分或者全部失去有利性,并导致后续的生理生化向全部失去或者部分失去其有利性的方向发展,致使相关有利性状消失或者向衰退的方向发展;最终致使自交子代相对于亲本衰退。基于有利遗传物质缺失致使自交衰退假说,提出内外协同物种濒危假说或者灭绝假说。该假说认为:由于有害外在因素(或者说有害外在环境)使生物大群体消亡变成或者分割变成小群体,小群体内生物容易发生近交,致使后代有利遗传物质缺失并导致一些相关的有利遗传物质部分或者全部失去其有利性,其后代适应外在环境的能力更差,更加容易死亡,导致群体数量进一步减少,进一步提升近交的概率,如此内因、外因协同恶性循环作用最终致使生物灭绝。提出了拯救濒危物种的技术方案。指出了杂种优势是一个相对性的概念,提出了研究杂种优势的简化方法,基于研究杂种优势的简化方法提出了研究杂种优势的最佳技术之一-基因编辑技术。基于研究杂种优势的简化方法和从有利遗传物质缺失致使自交衰退假说推导出进化意义上(以自然环境为标准)的杂种优势机理和育种上的杂种优势机理,最后归纳出杂种优势形成的一般或者通用规律,其内容是:在一定的生长环境下,依据一定的标准,(1)获得有利遗传物质不影响其它遗传物质致使杂交子代获得有利遗传物质相对应的有利性状;(2)除去有害遗传物质不影响其它遗传物质致使杂交子代相对应的有害性状消失;(3)获得有利遗传物质导致杂交子代体内一些相关的遗传物质获得有利性或者增加有利性或者减轻有害性或者除去有害性或者有害性转变为有利性,并导致后续的生理生化获得有利性或者增加有利性或者减轻有害性或者除去有害性或者有害性转变为有利性,致使获得相关的有利性状或者相关有利性状向获得优势方向发展或者相关有害性状向减轻有害性的方向发展或者除去相关有害性状或者相关的有害性状转变为有利性状;(4)除去有害遗传物质导致杂交子代后续可能发生一些的过程及结果同上。(5)获得父本、母本中一些相对比较好的遗传物质,替换或者除掉一些不如这些遗传物质的遗传物质,导致杂交子代后续可能发生一些的过程及结果同上。
This study firstly demonstrates that the genetic homozygosis of "recessive deleterious"alleles leading to that the inbreeding depression eventually comes down to its nature of the lack of beneficial genetic materials,followed by the definition of beneficial genetic material, harmful genetic material and neutral genetic material were defined and the proposal of law of genetic material elimination and law of genetic material superior.According to the law of genetic material elimination, under certain environmental standards, usually the more harmful genetic material is more likely to be eliminated while the more beneficial genetic material is less likely to be eliminated. Besides, the chance is higher that more harmful genetic materials are faster to be eliminated.According to the law of genetic material superior, under certain environmental standards, usually the more harmful genetic material is less likely to be passed on to the later generations or expanded to the community, while the more beneficial material is more likely to be passed on to later generations or expanded to the community.Likewise, the chance is higher that more beneficial genetic materials are faster to spread to the community. The genetic material composition theorem is deduced based on the two laws along with the elimination mechanism within biological bodies, which is: the organisms long evolving or long living in a long-term stable environment are carrying the following genetic materials on the standards of the environment: the majority or overwhelming majority is beneficial genetic materials with a generally small or an extremely small amount of neutral genetic materials. The possibility of the deleterious genetic materials rarely exists. Even if it does exist, the number should be only one or several. The new hypothesis of inbreeding depression is put forward based on the genetic material composition rule and existing differences on homologues. The new hypothesis suggests that in a stable environment for a long time, due to the differences existing in the genetic materials of homologues, the varied genetic materials or the genetic materials not simultaneously existing on the homologues are unlikely to exist in the filial generation after inbreeding, so that some beneficial genetic materials from the parents might go missing in the filial generation. Which could lead to two consequences: one is that the lack of beneficial genetic materials would not influence other genetic materials so that the beneficial characters brought by the beneficial genetic materials would disappear; the second is the lack of the beneficial genetic materials impacts on some relevant beneficial genetic materials to lose part of or all of benefits and further causes that the following physiology and biochemistry all head for the direction of losing part of or all of benefits, resulting in the disappearing of relevant beneficial characters and the development towards recession, and eventually leading to the inbreeding depression of the filial generation. Based on the hypothesis that the loss of beneficial genetic materials leads to the inbreeding depression,the consistent endangerment hypothesis or extinction hypothesis is put forward, stating that due to the deleterious external factors(or deleterious external environment), the extinction of large species has changed or subdivided to small groups, within which inbreeding easily happens among organisms, leading to an easier loss of beneficial genetic materials in the filial generation and thus losing part of or all of benefits in other relevant genetic materials.Consequently, it would be more difficult for the filial generations to adapt to the external environment, resulting in more deaths and shrink of group members, who inevitably further raises the possibility of inbreeding. Such a mechanism of vicious circle under internal and external influences would eventually cause the extinction. In the end, a technical plan is proposed to save the endangered species. It is pointed out that heterosis is a relative concept. A simplified method of studying the heterosis is proposed, which further derived gene editing technique,one of optimal techniques for studying heterosis. Based on the simplified method and the hypothesis that loss of beneficial genetic materials leads to the inbreeding depression, the mechanism of heterosis in evolution(according to the environment) and the mechanism iof heterosis in breeding is deduced, at last, the general mechanism of heterosis are summarized as below: In a certain growing environment, according to certain standards,(1) Obtaining the beneficial genetic materials without influencing other genetic materials to gain the beneficial characters accordingly in the hybrid filial generation;(2) Removing the harmful genetic materials without influencing other genetic materials to eliminate the harmful characters accordingly in the hybrid filial generation;(3) Obtaining the beneficial genetic materials leading to that some relevant genetic materials in the filial generation obtain or increase the benefits or reduce or eliminate harms. As a consequence, the following physiology and biochemistry obtain or increase benefits or reduce or eliminate harms, so that the relevant beneficial characters are obtained or developed in the direction of being obtained, or the relevant harmful characters are removed or developed in the direction of being reduced;(4) Removing the harmful genetic materials follows the same process and results in the same outcomes as above;(5) Obtaining some relatively beneficial genetic materials to replace or remove some less beneficial genetic materials, which follows the same process and results in the same outcomes as above.
作者
王浩
Wang Hao(Bijie Agricultural Institute, Bijie, 551700)
出处
《分子植物育种》
CAS
CSCD
北大核心
2017年第7期2762-2776,共15页
Molecular Plant Breeding
基金
贵州省科学技术基金(黔科合J字[2013]2003号)资助
关键词
遗传物质淘汰定律
遗传物质优胜定律
遗传物质组成定理
自交衰退新假说
生物濒危机制新假说
杂种优势新解
Law of genetic material elimination
Law of genetic material superior
Genetic material composition theorem
New hypothesis of inbreeding depression
Hypothesis for the endangerment mechanism
New theory of heterosis