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  Topic: Dolphins and Humans., Are we related? If so how close?< Next Oldest | Next Newest >  
Stephen Elliott



Posts: 1754
Joined: Oct. 2005

(Permalink) Posted: Jan. 25 2006,14:24   

Does anyone know if a genome comparison has been done between humans and dolphins?

I have tried to google it, but I am not sure wether I am getting crank sites or not.

Didn't spot anything obvious on T.O. either. Maybe I need spectacles.

I am curious how closely we are related to dolphins (or any other marine mamal) as compared to chimps or other apes.

  
argystokes



Posts: 766
Joined: Jan. 2006

(Permalink) Posted: Jan. 25 2006,14:58   

Well, the only animal genomes that have been sequenced are humans, rats, dogs, chickens, and fruit flies.  I'm unaware of any studies (and I'm sure your internet search is as good as mine).  I don't suppose there's really any impetus for the comparison.

I'd guess we're about as similar to dolphins as we are to cows, as they both belong in the same clade.  The higher intelligence of humans and dolphins would be an example of convergent evolution.

--------------
"Why waste time learning, when ignorance is instantaneous?" -Calvin

  
Henry J



Posts: 4947
Joined: Mar. 2005

(Permalink) Posted: Jan. 25 2006,15:03   

Well, Eutheria (placental mammals) says it was last updated 1995, so I've no idea if data has changed since then, and that chart shows cetacia as an offshoot of hooved mammals - about as far from primates as something can get without being an anteater or pangolin.

Otoh, bats aren't too far from primates on the tree... :)

Henry

  
Stephen Elliott



Posts: 1754
Joined: Oct. 2005

(Permalink) Posted: Jan. 25 2006,15:11   

Cheers for the replies.
What I was trying to find was the % difference in the genome.

ie. Humans ->Chimpanzies C2-5% difference depending on the way it is measured.

I was loking for the Human->Dolphin % difference.

Maybe the comparison has not been done. ???

  
Flint



Posts: 478
Joined: Jan. 2006

(Permalink) Posted: Jan. 25 2006,15:57   

I strongly doubt that such a comparison would be very meaningful. Sure, it would indicate that mammals are related to one another in some ways. But I think that the statement that humans and chimpanzees are 99% identical is misleading. It only takes a couple of differences, especially in development, to make truly major differences in the morphology and entire behavioral pattern of the organism.

On the other hand, maybe some of our creationists, for whom macroevolution is impossible, might be interested in how apparently macro some truly micro genetic differences might lead to.

Didn't I read somewhere that humans have a 40% genetic overlap with snap beans?

  
gregonomic



Posts: 44
Joined: Dec. 2005

(Permalink) Posted: Jan. 25 2006,17:55   

I doubt there has been much dolphin genome sequencing done, so if it's dolphin specifically you're looking for, I can't help you.

But the genome of a relatively closely related terrestrial mammal, the cow (Bos taurus), is currently being sequenced, and there is already quite a lot of data in the databases.

For an analysis of a large (1.8 Megabase) region corresponding to part of human chromosome 7 (including the cystic fibrosis transmembrane conductance regulator, CFTR, aka "the cystic fibrosis gene") in 12 vertebrate species, see:

Thomas et al, 2003, Nature, 424(6950):788-93. Comparative analyses of multi-species sequences from targeted genomic regions.

For more recent phylogenies of mammals see:

Murphy et al, Nature. 2001 Feb 1;409(6820):614-8. Molecular phylogenetics and the origins of placental mammals.

Madsen et al, Nature. 2001 Feb 1;409(6820):610-4. Parallel adaptive radiations in two major clades of placental mammals.

Liu et al, Science. 2001 Mar 2;291(5509):1786-9. Molecular and morphological supertrees for eutherian (placental) mammals.

  
gregonomic



Posts: 44
Joined: Dec. 2005

(Permalink) Posted: Jan. 25 2006,17:58   

By the way, Stephen, are you looking for % identity in exons (ie. protein-coding) regions (which will be most similar) or intergenic regions (less conserved)?

  
Dean Morrison



Posts: 216
Joined: Dec. 2005

(Permalink) Posted: Jan. 26 2006,01:37   

If you are thinking we share similarly highly developed intelligence - then this is probably due to the evolutionaly advantage this is to an animal living in a co-operative social group (especially in co-operative hunting). Communication and language require the development   and growth of specialised parts of the brain.

We are each probably more closely related 'non-social' animals which haven't developed intelligence to the same degree as it doesn't confer evolutionary advantage - and Brains are high maintenance.

We are more closely related to fairly dumb bush-babies for example - whilst dolphins are more closely related to sheep .

The 'Ancestor's Tale' by Dawkins is a great book if you are interested in how closely we are related to other groups. It start with humans and works backwards through time. Various other groups join us on the way back to the beginning of time - as 'pilgrims in the Canterbury Tales' - the 'conceit' of the book.

When we meet up I'll lend it to you Steve - as long as you promise to let me have it back ;)

  
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