Roses and species concept

As this is another topic I reply here to “Breeding from species” contributions.


I do not at all think DNA is the last word. usefull for cultivars that share all to most ancestry but certainly not for species.

I learned recently that french scientist were more than considering to map the estimated 5000 microorganisms that inhabit our digestive system. When we know so little of the studied small minority, no more than a name and hints for the majority and an ample part is even nameless.

Our Knowledge of DNA is similar: we know how to map it, we learn how a little part is working, there are many that have but a name and an ample share about which nothing to very little is known.

It is the problem genetical manipulators face.

DNA maping is taking an identity photo. One cannot infer someone

Pierre, the most successful species do not exist in isolated populations. They exist over large geographic areas.

They can vary greatly within those areas and in some cases merge with other species near the borders of their natural range.

I understand the point you make, yet trying to determine the most representative example of any species is in my opinion subjective.

What do we consider the most definitive example of any species?

As I’ve said, humans tend to seek out those examples of species that are unusual or to our mind superior for use in hybridizing. Such examples are not average to begin with and as such are not the most representative examples of species.

An then how do we know the phenotypic expression of any species we select doesn’t harbor atypical genotype?

Nothing is absolute unless we agree to accept the absolute. We must accept the opinion of others and our access to species clones made available. That’s my point.

DNA can only be compared to an accepted archetypal absolute. DNA is useful for determining affinity to other accepted absolutes. We have to start somewhere.

Robert, I agree with many things you wrote such as:

“Nothing is absolute unless we agree to accept the absolute.”

And that a specimen cannot personify a species.

Only one can try to choose a few.

I know some species are not well defined such as i.e. some american tetraploids or european Caninae.

And I did not write maping DNA is useless. Only that “I do not at all think DNA is the last word”. That studying it being usefull is obvious but it is far from being all and everything.

Years ago I met on the web a renowned cacti DNA chloroplast specialist that theorized about lineages just forgiving that the said chloroplasts were maternaly only inherited…

Friendly yours. Pierre