A genetically modified plant or animal has had some of its genes changed scientifically.

Mickey Mouse 8241Why is the bold section written in 'causative form' ?

Because somebody changed the genes of the animal or plant, i.e., caused the genes to change. The animal or plant would not have been able to do that by itself.

Mickey Mouse 8241W

Mickey Mouse 8241 'causative form' ? what does it mean?

It means that some scientists in a laboratory tinkered with the organism's genome and changed it.

CalifJimBecause somebody changed the genes of the animal or plant, i.e., caused the genes to change. The animal or plant would not have been able to do that by itself.

Thanks teacher.

Could we use 'passive forms' instead of 'causative'? Is the meaning the same?
In GM technology, plants or animals' genes have been changed scientifically.

Mickey Mouse 8241In GM technology, plants' or animals' genes have been changed scientifically.

This sentence is also correct, both grammatically and factually, but it loses the sense of being a definition of "genetically modified". Now it's more like a statement of the achievements of GM technology.

CJ

Mickey Mouse 8241A genetically modified plant or animal has had some of its genes changed scientifically.

I 'feel' the passive voice in the sentence above. I can't exactly pinpoint why I've got that 'feeling', especially that the lack of the helping "to be" exclude it as a sentence in the passive. On the other hand, it is that they have modified and change

AnonymousI 'feel' the passive voice in the sentence above. I can't exactly pinpoint why I've got that 'feeling'

It's from "changed", "had (something) changed" ~ "was changed (by something/someone)", more specifically "was caused to be changed (by something/someone)".

In the paraphrase it's doubly passive. See the underlining.
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AnonymousI 'feel' the passive voice in the sentence above.

Yes, the passive voice is in causative constructions. It works with infinitives and inflected forms.

Last week, I had my hair cut. (by the hairdresser)
Today I will have my car repaired. (by the mechanic)
Next year we plan to have our house painted. (by the painters)
I have had my

Note the difference between the third form (past participle) and the bare infinitive. The former is passive in meaning with causative HAVE, the latter active.

I'll have my car repaired (by the mechanic).
I'll have the mechanic repair my car.

CalifJimmore specifically "was caused to be changed (by something/someone)".

Yes, I see it now. Thank you very much for the detailed explanation.