question on monocot flower development

[Jerrold I Davis]

Hi --

You know your needs best, but if my opinion were sought I would recommend 
that you NOT create a separate system for monocots and dicots.  We do use 
the same general terms for floral parts in both groups, and arguments 
concerning separate origins are fairly speculative.  On re-reading my 
earlier note, in which I suggested that the case for separate origins had 
been strengthened of late, I feel that I may have overstated the 
case.    There really is no compelling case that I know of for treating the 
floral parts of monocots and dicots as different things.

Another argument agains a dicot/monocot distinction lies in the fact that 
the monocots are phylogenetically nested within the dicots.  Thus, some 
dicots are more closely related to monocots than they are to other dicots:

              _____ dicot 1
              |
--------------    _____ monocots
              |    |
              |-----
                   |____ dicot 2


So the old monocot/dicot distinction is misleading, and it might turn out 
that any peculiar floral attributes of monocots are shared with some 
dicots, but not with others.  By setting up a dichotomy out the outset, one 
may tend to obscure this situation.  Better to let the data accumulate, I 
would argue, and see how the chips fall.

Best,

Jerry Davis





At 09:31 AM 5/26/2004 Wednesday +0100, you wrote:
>Hi Jerrold,
>
>Thank you for your comments. I think it would be very interesting to 
>consider subgroups within the dicots further down the line. However, right 
>now we are just trying to cover the two groups: dicot and monocot. We've 
>found in the past that if we try to make large sections of ontology 
>covering lots of different species at once then things can get so 
>complicated that we never reach the implementation stage. That's why we're 
>sticking to solving one problem at a time.
>
>Pankaj has conveyed my question very well below. The motivation behind 
>this question is that I need to make the terms: sepal development, petal 
>development, stamen development, carpel development, for dicots. I would 
>like to know whether the monocot annotators will need a sensu version of 
>the same terms, or whether these flower parts would have different names 
>in monocots anyway.
>
>Thanks,
>
>Jen
>
>
>
>
>
>
>Jerrold I Davis wrote:
>
>>Pankaj:
>>
>>Through the years, it has often been hypothesized that various floral 
>>parts of monocots and dicots (generally perianth parts, as opposed to 
>>stamen or pistil) have arisen independently.  This view of things has 
>>been strengthened in recent years by the placement of various apetalous 
>>taxa as early-divering elements within the dicots.  However, there are 
>>also many potential cases of parallel gains and gain/loss/gain events 
>>among dicots alone, so I would be wary of any attempt to distinguish 
>>monocots from dicots while failing to address equally or more compelling 
>>cases within the dicots.
>>
>>Jerry
>>
>>
>>At 11:16 AM 5/25/2004 Tuesday -0400, you wrote:
>>
>>>Hi Everyone,
>>>
>>>I have a question on flower development in Monocots. The reason I am 
>>>asking this is because I am working with Gene Ontology group 
>>>(www.geneontology.org) to introduce the biological process that 
>>>represent a flower development. While doing this we need to instantiate 
>>>whether,
>>>
>>>-It is possible to do most of the gene expression and phenotype 
>>>annotation using a generic term or do we need a monocot and dicot 
>>>specific term?.
>>>-Is there a conceptual difference between the development of a monocot 
>>>and dicot flower and its parts? e.g. is there a difference between a 
>>>monocot and dicot anther/carpel/petal/sepal/tepal development.
>>>
>>>
>>>Thanks
>>>Pankaj
>>
>>
>>
>>______________________________
>>
>>Jerrold I Davis
>>Associate Professor
>>
>>Department of Plant Biology
>>(office: 214 Plant Science Building)
>>(mailing address: 228 Plant Science Building)
>>Cornell University
>>Ithaca, New York 14853
>>U.S.A.
>>
>>phone:   607-255-7980
>>fax:     607-255-5407
>>e-mail:  JID1 at cornell.edu
>>______________________________
>>