Thanks Tanay and Sid The discussion is getting interesting.
-- Dr. Gurcharan Singh Retired Associate Professor SGTB Khalsa College, University of Delhi, Delhi-110007 Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018. Phone: 011-25518297 Mob: 9810359089 http://people.du.ac.in/~singhg45/ On Thu, Jul 29, 2010 at 3:46 PM, Sid <[email protected]> wrote: > > Dear Tanay, > > Your theory is absolutely possible. In a recent study by Bruneau et al., > (2008) the "Amherstiae" clade is found to be monophyletic. It includes > Tamarindus and the age of this clade is estimated approximately around 52 > million years. This paper discusses that the origion of Fabaceae since 65 > million years ago (late Cretaceous). > > Sid. > > > On 29 July 2010 12:45, tanay bose <[email protected]> wrote: > >> Raven and Polhill (1981) in the same paper also suggested a relative time >> of evolution of Fabaceae members which is Upper Cretaceous based on well >> defined subfamilies (Caesalpinioideae, Mimosoideae and Papilionoideae) that >> were in existence by the Cretaceous. The paper clearly states the sampling >> region which is Asia, Africa and Madagascar. Within Asia the population has >> only been recorded as wild from India where as in Thailand it was recorded >> as planted. >> >> Before moving any further into the topic it will be quite reasonable to >> keep the map of the earth during Upper Cretaceous (kindly use the map >> attached tentative map attached with this mail) in our mind. The map clearly >> indicates that the two continents have clearly just parted which are South >> America and Africa. Cameroon (a sampling country in the paper) is in West >> Africa which is placed exactly at the western major groove of Africa. The >> coastline through which Amazon comes out into Atlantic Ocean is same in >> architecture like the West African coastline which we all are aware of while >> studying continental drift theory. >> >> Now if we assume that the plant like *Heterostemon* has similarity with >> *Tamarindus >> indica* then probably it is a close ancestor of it or the mother >> organism. If *Heterostemon* from upper Amazon has similarity then there >> should me some evidences in middle and lower Amazon in form of fossils for >> *T indica*, or any kind of transitional plant (hence I assume this theory >> as speculative and not affirmative). The plant was found in Cameroon (West >> Africa) and East Africa but no evidence was found in central Africa which >> could have highlighted the probable migration pathway. At the same time in >> the south east cost of Africa, Madagascar and India are also parting out >> hence quite possible that they will have some vegetation common with the >> ancient or present vegetation of East Africa. In Asia no other counties have >> similarity with Indian flora because India is a piece of migrated land from >> Africa and not a part of original Asia. It’s quite reasonable that *T >> indica* came to Asia because of Indian plate migration. >> >> Now if I say that the process was different the plant evolved in Indian >> portion of the then Africa and migrated to present East African countries >> though Madagascar we can draw a clear line of pathway which is more >> continuous than the previous one. If we don’t find high diversity within a >> particular species population that doesn’t confirm that the region has no >> contribution on its evolution. There are several such records were we find a >> plant is extinct in a region from where it evolved but found else where, >> does this harm its evolution strategy? If not then why won’t this be the >> case for *T indica*? Probably *T indica* truly evolved in India but >> during the course of migration, land reformation, climatic variation (during >> the Upper Cretaceous) the pollution of this plant was affect which has >> ultimately decreased the variation. >> >> >> Kindly consider this theory as a probability and not affirmative. >> >> >> >> >> >> Map of world during Upper Cretaceous: >> >> http://en.wikipedia.org/wiki/File:LateCretaceousGlobal.jpg >> >> >> >> >> >> >> >> Tanay >> >> >> On Thu, Jul 29, 2010 at 9:11 AM, Sid <[email protected]> wrote: >> >>> Dear Friends, >>> >>> This is an interesting discussion about Tamarind. The RAPD paper doesn't >>> exactly answer about the origin of Tamarind. As a whole the sampling within >>> India (Asia) and Madagascar is sparse. Even the title ends with a question >>> mark. Moreover the authors say they could not find references >>> paleontological evidence of Tamarind pollen in the tertiary (whereas other >>> genera could be found) again mystifying the origin of Tamarind in Africa. >>> >>> But based on the fact that Africa is the origin of most genera of the >>> tribe (25 genera of Amherstieae (Tamarindus tribe), 23 are endemic to Africa >>> and Madagascar :Polhill and Raven (1981)), it might be concluded that the >>> genus originated in Africa. I could not find any recent well resolved >>> molecular phylogeny of the group. In Bruneau et al., (2001), Tamarind is in >>> the Amherstieae clade. The clade is also not well resolved probably do the >>> lack of enough polymorphisms in the DNA sequence. So there is no clear >>> evidence of the phylogenetic relatives of Tamarind. Prehistoric long >>> distance dispersal into India/Asia by birds might also be not ruled out as a >>> source of entry into India. A molecular study to find out the origin of our >>> beloved Tamarind would be very interesting. >>> >>> Sid. >>> >>> >>> On 29 July 2010 09:30, Gurcharan Singh <[email protected]> wrote: >>> >>>> I does'nt, whether you like it or not. I hope you know why and what >>>> people write in abstract. >>>> >>>> >>>> -- >>>> Dr. Gurcharan Singh >>>> Retired Associate Professor >>>> SGTB Khalsa College, University of Delhi, Delhi-110007 >>>> Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018. >>>> Phone: 011-25518297 Mob: 9810359089 >>>> http://people.du.ac.in/~singhg45/ <http://people.du.ac.in/%7Esinghg45/> >>>> >>>> >>>> >>>> On Wed, Jul 28, 2010 at 11:11 PM, Pankaj Kumar >>>> <[email protected]>wrote: >>>> >>>>> Thanks a lot for reading the aritcle..... >>>>> >>>>> Page no. 854, paragraph 3, line no. 18: Tamarindus is said to have >>>>> some resemblance to Heterostemon Desf. from the upper Amazon region of >>>>> South America. >>>>> >>>>> Page no. 857, paragrah 2, line no. 1: The high intra population >>>>> variability from the populations of the presumed origins of T. Indica >>>>> do not allow for confirmation of the geographical origin of the >>>>> species between Africa, Madagascar and India, as the sampling was >>>>> small in Asia and Madagascar. >>>>> >>>>> Hope that contradicts the information provided earlier. >>>>> Regards >>>>> Pankaj >>>>> >>>> >>>> >>>> >>>> >>> >> >> >> -- >> Tanay Bose >> +91(033) 25550676 (Resi) >> 9830439691(Mobile) >> >> >>
