Whatever may appear, it is possible. You made three three points: new, beneficial, functional.
1 New
Start with a piece of DNA: GATTACA
Duplicate it: GATTACA GATTACA
Mutate one copy: GATGACA GATTACA
The final state has increased the amount of information in the genome measured both as Shannon information and as Kolmogorov information. We can observe gene duplications in nature and in the laboratory. We have a number of them in our own genomes. We can observe point mutations in nature and in the laboratory. We can observe point mutations in duplicated genes in our own genomes - we have many different globin genes: myoglobin, haemoglobin-alpha, haemoglobin-beta and the various foetal haemoglobins. All of these different globing were derived by just the process above, along with a number of broken globin pseudogenes.
3 Functional
I will deal with functional before beneficial because all beneficial genes must be functional by definition, but not all functional genes must be beneficial. Most mutations are neutral, they have no effect on our phenotype at all. Some mutations are functional but neutral - for example it is probable that the genes for eye colour are selectively neutral. They have a function but they are not beneficial.
There are many functional mutations, for example the various responses to malaria in humans. Many of these are new. There are also mutations which provide some resistance to HIV, again these mutations are functional.
2 Beneficial
A new mutation may be both functional and beneficial, for example the Apolipoprotein AI-Milano mutation which protects aganst chloresterol in the Western diet and which arose within the last 300 years in North Italy: see
A Rare Protein Mutation Offers New Hope for Heart Disease Patients.
In malarial areas the anti-malaria mutations such as Hb-S and Hb-C are beneficial. The various anti-HIV mutations are also beneficial. The Native Americans were denied the benefits of the anti-smallpox mutations posessed by the European settlers; those mutations were beneficial for some but not for others, indirectly.
In summary new information can be added to genomes. The new information can be functional and the new information can be beneficial.
I spent a whole five minutes looking at a blade of grass and it didn’t grow at all! It does not appear possible for grass to grow.
Don’t use fruit flies, use bacteria. They can evolve resistance within weeks, see the
the Luria-Delbrück experiment. Alternatively speed up the mutation rate by using a radioactive source, then you will see new and functional (though usually not beneficial) information.
rossum