How many plants have you sequenced? How long are the sequences and what kind of loci or gene are they? In other words can yo describe your data?

What is your criteria for determining endemism?

Hello Patrice Showers Corneli,

My plant is already recorded as endemic since long time ago. I would like to authenticate and confirm this idindification and endemic status. I sequenced ITS region and trnH/psbA from very few samples. The ITS region ranged from 500-680 bp. The chloroplast marker ranged from 350-400 bp.

To be honest I don't think you can confirm endemism using genetic data. However if the sequences do not mach sequences from plants collected in other areas I guess you can use that as support for a restricted range of the species, but a weak support as many species still lack published sequences.

I agree very much with Svante. I do not think that genetic data can separate species simply because the process is a continuous one that seldom has clear boundaries and even when sequences appear very different, the boundaries proposed by those fond of barcoding are quite arbitrary.

You can never prove an hypothesis. You can, however, find out if the sequences more strongly resemble other populations than the local population which this plant is purported to be.

The way you do that is to have the same genetic sequences for distant populations and for some local samples that you are certain are endemic. If you do not have the comparative data then you cannot test for endemism. If you do (say from your own sample or from a data base such a Genbank) then you can provide evidence that sample seems more closely related to a distant population than local ones.

Barcoding is fraught: a tiny sample of genes to determine species level differences (which are quite arbitrary in any case) seems foolish to me.

But if you have the comparative data, you might be able to actually conclude that "From these data, the sequence appears more closely related to local population than to distant populations" or on the contrary "the sequence more closely resembles a distant population and there is no evidence for endemism". Or "these sequences provide no evidence regarding the endemism."

Isn't endemisim by definition about the limited geographical range of a concerned sepecies, in this case a plant species. To veryfy such a claim for a species one would simply consult herbaria for the distributional range data of the species or to do more field collection of the distribution of the species. Molecular data and techniques may only be relevant should we need to veryfy if related species found elsewhere are same or different to the species of interest, in combination with the any traditional plant taxonomic morphometric and meristic variables such as floral and fruit morphology and anatomy, and leaf morphology and architecture.

I think Dr. Mungkaje has hit the nail on the head.

You first need to look through historic records to see where the species has been recorded and look for information in regards to its emergence in new localities. However, there will be no way to confirm that the records are completely accurate.

Only once you've done this ground work wil, thenl molecular data come into play. Using phylogenetics you will be able to determine diversification and divergence.

This data will need to be interpreted in tandem with records.

However, readily identifiable differences may not be witnessed. As species move between geographic regions (facilitated by various factors) there is nothing to suggest there was a single invasion event. If there have been multiple instances of invasion or reverse invasion you may not see any divergence at all.

Dear Ahmed,

glad to meet you again on the Internet !

Indeed your question includes two questions :

1) How can I assess the endemism of a plant ?

2) How can the sequenced loci (here classical barcode loci) help me ?

I would like you to answer this :

1) To assess endemism you have to collect several individuals and populations of your studied plant covering its whole known distribution area. Then collect several individuals and populations of ALL presumed related plants (at least the close species, at best the whole genus). Finally you have to make a comparative analysis of all these data, independantly of the choosen method (morphology, genetics, other) and ideally with a combined approach ! If all plants similar to yours are limited to your area, it is endemic, if you discover foreign plants that are "very similar" (if not identical), then it is no more endemic...

2) The barcoding (and other kind of phylogenetics) can help you to known the systematics position of the sister taxa of your plant (origin of the endemism) AND to estimate the time divergence of these ancestral common relationship (oldness of the endemism). This latter point can help you to consider if it is an old and isolated endemism (a "good" species therefore a "good endemic") or if it is not a really good taxa (and then not reasonnably being considered as endemic). In this case the first point of answer 2 help you to understand to which very close group your peculiar plant is really belonging...

Is it clear for you now ?

All the best,

Errol.