RSS 2.0 Feed

» Welcome Guest Log In :: Register

    
  Topic: Hybrid Speciation, is it or ain't it< Next Oldest | Next Newest >  
Erasmus, FCD



Posts: 6349
Joined: June 2007

(Permalink) Posted: Sep. 23 2007,22:54   

Anybody interested in this?  Seems like there is a growing literature that makes some strong arguments.  Plants are weird, ploidy issues make it a slam dunk case since they are automatically reproductively isolated.  In animals, it is not so clear but there are some good candidates.

Of course, it is a theory of the gaps since it's easy to equivocate around definitions of 'hybrid' since we are probably using different definitions of 'species'.  I'm reading the new Arnold book about hybridization and evolution and I'm impressed with the concept of reticulating lineages and the possibility that gene flow between lineages can increase genetic variability for selection to work on.  

I know some strong critics and some strong proponents and it's hard to disagree with either side since often there is a disparity in common definitions of terms and philosophy (slippery slope definitions of hybrid lineages, etc).  I am working on a group of insects where reticulation is a strong hypothesis.  Morphological taxonomic approaches have been incomplete at best and we are the first to take the molecular approach.  And it's a mess so far.

--------------
You're obviously illiterate as hell. Peach, bro.-FtK

Finding something hard to believe based on the evidence, is science.-JoeG

the odds of getting some loathsome taint are low-- Gordon E Mullings Manjack Heights Montserrat

I work on molecular systems with pathway charts and such.-Giggles

  
someotherguy



Posts: 398
Joined: Aug. 2006

(Permalink) Posted: Sep. 23 2007,23:10   

Quote (Erasmus, FCD @ Sep. 23 2007,22:54)
I'm reading the new Arnold book about hybridization and evolution and I'm impressed with the concept of reticulating lineages and the possibility that gene flow between lineages can increase genetic variability for selection to work on.

I'm fairly interested in this topic (although not knowledgeable by any means!).  Which book are you referencing here?

--------------
Evolander in training

  
jeannot



Posts: 1200
Joined: Jan. 2006

(Permalink) Posted: Sep. 24 2007,04:18   

Talking about hybrid speciation, there's a relatively recent study in Nature, where they could recreate a hybird species of butterfly in the lab. I'll try to find a link.

It should be mentioned that there are two models of hybrid speciation. One that involve polyploidy, and one that doesn't, which is more complicated and not completely understood.

EDIT : here you go: Nature 441, 868-871 (15 June 2006)
Speciation by hybridization in Heliconius butterflies

Jesús Mavárez1,4, Camilo A. Salazar2,4, Eldredge Bermingham1, Christian Salcedo2, Chris D. Jiggins3 and Mauricio Linares2
Quote
Speciation is generally regarded to result from the splitting of a single lineage. An alternative is hybrid speciation, considered to be extremely rare, in which two distinct lineages contribute genes to a daughter species. Here we show that a hybrid trait in an animal species can directly cause reproductive isolation. The butterfly species Heliconius heurippa is known to have an intermediate morphology and a hybrid genome1, and we have recreated its intermediate wing colour and pattern through laboratory crosses between H. melpomene, H. cydno and their F1 hybrids. We then used mate preference experiments to show that the phenotype of H. heurippa reproductively isolates it from both parental species. There is strong assortative mating between all three species, and in H. heurippa the wing pattern and colour elements derived from H. melpomene and H. cydno are both critical for mate recognition by males.

  
Erasmus, FCD



Posts: 6349
Joined: June 2007

(Permalink) Posted: Sep. 24 2007,08:37   

Book

Michael Arnold 'Evolution through genetic exchange'

jean the plant ploidy thing is much easier to understand.  i know a fella trying to work out a model for the heliconias example and his results are puzzling.  it is difficult to fine tune the model such that the new species does not wipe out the parentals via introgression from backcrossing.  

there is another example from Lepidoptera in the Lycaiedes genus.  the putative hybrid species has a genome mosaic composed the of the two parentals.  there is also ecological divergence...  see Science 22 December 2006:
314: 1923 - 1925 Homoploid Hybrid Speciation in an Extreme Habitat
Zachariah Gompert,1 James A. Fordyce,2 Matthew L. Forister,3 Arthur M. Shapiro,4 Chris C. Nice1*

--------------
You're obviously illiterate as hell. Peach, bro.-FtK

Finding something hard to believe based on the evidence, is science.-JoeG

the odds of getting some loathsome taint are low-- Gordon E Mullings Manjack Heights Montserrat

I work on molecular systems with pathway charts and such.-Giggles

  
  3 replies since Sep. 23 2007,22:54 < Next Oldest | Next Newest >  

    


Track this topic Email this topic Print this topic

[ Read the Board Rules ] | [Useful Links] | [Evolving Designs]