Effects Of Feces Of Human Lysozyme Ransgenic Goat On Soil Microbial Community And Orizontal Gene Transfer

In recent years, the research of transgenic animal is gradually developed, from theory topractice, and it plays an important role in promoting the economic development of the society.However there has been a debate concerning the safety of transgenic animals, which attractedmach attention of worldwide institutes to dedicate into the related researches. The safety oftransgenic animal study is still at the initial stage compared with the same research intransgenic plants and there is no such study of effects of transgenic animals on thesurrounding environment so far. Meanwhile, that most transgenic animal safety studies arefocused on the animal’s own health and welfare rather than their influence to environment.In this study, the soil samples mixed with feces were derived from the barn where thehLYZ transgenic lived to study the possible gene drift of human lysozyme to the surroundingenvironment by PCR and its influence on the soil microbial community structure throughDGGE technology. To investigate the positive human lysozyme transgenic milk goat’senvironment safety. Furthermore, the soil samples derived from goat barn are affected bymany factors in the environment. Thus it is unable to accurately conclude that any changes insoil microbial community is caused by the transgenic goats just based on the experimentabove. So another experiment was designed by mixing the same source of soil with sameportion of feces from transgenic goats and wiled type goats. The same method was performedto get the results of the soil microbial community structure and horizontal gene transfer. Ourexperiment results showed that:(1) The diversity and structure of microflora were both more abundant in the soil fromtransgenic and wild type goat barn than the one without feces of goats. This suggests thatthe growth of microorganism in soil was beneficial from the daily waste of goats.(2) There was a high similarity (>95%) of the structure of microbial community aftercomparing the soil samples from the barn’s of transgenic and wild type goats. Among them,Proteobacteria, Bacteroidales and Firmicutes are the three dominant microorganism groupsand the relative amounts of each group in the two soil samples are close, which indicates thatthe feces of transgenic goats do not have an adverse affect on the environments.(3) The mixed soil samples with feces of transgenic and wild type goat were left in natural environment After a period of time, the diversity of microbial community were allincreased with two types of sample compared with the pure soils. Meanwhile, The tendencyof the structure change of soil microbial community was also different between pure soil andthe one mixed with feces.(4) In addition, the structure of the microbial community were similar in the two soilsamples with feces of transgenic and wild type goat and it was more than93%similar of thesample taken in same time. Both samples contained the same dominant bacterial groups,Proteobacteria, Bacteroidales and Firmicutes as well as the same tendency regarding thestructure change of the microbial community, which suggests that the impact of feces fromtransgenic goats on the soil microbial community is similar to the effected by the feces fromwild type goat.(5) There was no transgene, hLYZ, detected in microbial DNA extracts of topsoil byPCR. The result suggests that the foreign gene will not be flowed to the environment viahorizontal gene transfer.Generally, we conclude that the transgenic goats do not effect the soil microbialcommunity and no gene drift is occurred.