Miceta et al 2013 - Myoglobin Evolution Paper

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Miceta et al 2013 - Myoglobin Evolution Paper

Postby AlgisKuliukas » Sat Jul 06, 2013 12:20 pm

Mirceta, S., Signore, A., Burns, J., Cossins, A., Campbell, K., Berenbrink, M. Evolution of Mammalian Diving Capacity Traced by Myoglobin Net Surface Charge. Science 340:1234192:1-8, (2013).

Extended breath-hold endurance enables the exploitation of the aquatic niche by numerous mammalian lineages and is accomplished by elevated body oxygen stores and adaptations that promote their economical use. However, little is known regarding the molecular and evolutionary underpinnings of the high muscle myoglobin concentration phenotype of divers. We used ancestral sequence reconstruction to trace the evolution of this oxygen-storing protein across a 130-species mammalian phylogeny and reveal an adaptive molecular signature of elevated myoglobin net surface charge in diving species that is mechanistically linked with maximal myoglobin concentration. This observation provides insights into the tempo and routes to enhanced dive capacity evolution within the ancestors of each major mammalian aquatic lineage and infers amphibious ancestries of echidnas, moles, hyraxes, and elephants, offering a fresh perspective on the evolution of this iconic respiratory pigment Introduction: Evolution of extended breath-hold endurance enables the exploitation of the aquatic niche by numerous mammalian lineages and is accomplished by elevated body oxygen stores and morphological and physiological adaptations that promote their economical use. High muscle myoglobin concentrations in particular are mechanistically linked with an extended dive capacity phenotype, yet little is known regarding the molecular and biochemical underpinnings of this key specialization. We modeled the evolutionary history of this respiratory pigment over 200 million years of mammalian evolution to elucidate the development of maximal diving capacity during the major mammalian land-to-water transitions. Methods: We first determined the relationship between maximum myoglobin concentration and its sequence-derived net surface charge across living mammalian taxa. By using ancestral sequence reconstruction, we then traced myoglobin net surface charge across a 130-species phylogeny to infer ancestral myoglobin muscle concentrations. Last, we estimated maximum dive time in extinct transitional species on the basis of the relationship of this variable with muscle myoglobin concentration and body mass in extant diving mammals. Results: We reveal an adaptive molecular signature of elevated myoglobin net surface charge in all lineages of mammalian divers with an extended aquatic history—from 16-g water shrews to 80,000-kg whales—that correlates with exponential increases in muscle myoglobin concentrations. Integration of this data with body mass predicts 82% of maximal dive-time variation across all degrees of diving ability in living mammals. Discussion: We suggest that the convergent evolution of high myoglobin net surface charge in mammalian divers increases intermolecular electrostatic repulsion, permitting higher muscle oxygen storage capacities without potentially deleterious self-association of the protein. Together with fossil body-mass estimates, our evolutionary reconstruction permits detailed assessments of maximal submergence times and potential foraging ecologies of early transitional ancestors of cetaceans, pinnipeds, and sea cows. Our findings support amphibious ancestries for echidnas, talpid moles, hyraxes, and elephants, thereby not only establishing the earliest land-to-water transition among placental mammals but also providing a new perspective on the evolution of myoglobin, arguably the best-known protein.
Waterside hypotheses of human evolution assert that selection from wading, swimming and diving and procurement of food from aquatic habitats have significantly affected the evolution of the lineage leading to Homo sapiens as distinct from that leading to Pan. (p118)
Kuliukas, A., Morgan, E. (2011). Aquatic scenarios in the thinking on human evolution: What are they and how do they compare?. In: Vaneechoutte, M., Verhaegen, M., Kuliukas, A. (2011). Was Man More Aquatic in the Past?
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Re: Miceta et al 2013 - Myoglobin Evolution Paper

Postby AlgisKuliukas » Sat Jul 06, 2013 12:40 pm

In a nutshell, they assayed myoglobin in a few extant mammalian species and found a molecular marker (indicative of net surface charge) that correlated with the amount of diving they did. Then, they used the ever growing genome database to estimate the amount of surface net charge in myoglobin acrosss mammals of all the major orders and found that, in almost all caases, there was a clear correlation between the net surface charge and degree of aquatic adaptation.

The one major outlier were Sirenia - manatatees and dugong, who had myoglobin levels indicating that it had not evolved along the same lines as other aquatics. Humans had similar levels to manatees/dugongs - at the opposite end of the spectrum to aquatic/semi-aquatic mammals. Even less than chimps!

This image summarises the whole paper beautifully...
Image

This image, from the supplimentary materials, shows humans...
Image
... of course the two recent mutations (on the Pan line and the Pongo line) are probably just random, so I do not think anyone should take too much note of those - but if humans had dived significantly more than chimps since the LCA one would predict a mutation or two making the myoglobin net surface charge bigger in humans.

Algis
Waterside hypotheses of human evolution assert that selection from wading, swimming and diving and procurement of food from aquatic habitats have significantly affected the evolution of the lineage leading to Homo sapiens as distinct from that leading to Pan. (p118)
Kuliukas, A., Morgan, E. (2011). Aquatic scenarios in the thinking on human evolution: What are they and how do they compare?. In: Vaneechoutte, M., Verhaegen, M., Kuliukas, A. (2011). Was Man More Aquatic in the Past?
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Re: Miceta et al 2013 - Myoglobin Evolution Paper

Postby DDeden » Tue Aug 19, 2014 3:13 am

Were data on Sea Otters (California) and Marine Otters (Peru) included? Were both freshwater manatees and marine dugongs included in the study?

Apparently Marine Iguanas (Galapagos) compared to desert and jungle iguanas, as well as sea snakes and hypothetically extinct ichthysaurs, all being reptiles, were excluded, unfortunately.

It seems that both Endurance Running and Endurance Diving in ancient Hominins are not well demonstrated by data.

Are ancient Neanderthal or Denisovan genomes indicative of higher myoglobin capacity compared to modern AMH Hss? Possibly the advent of boating in the last 50,000 years may have reduced selection for apnea in Hss. as has massive selection for lowland agriculture more recently.

Note a recent article in Nature showing that Tibetans with oxygen hemoglobin hypoxia resistance have Denisovan genes active: "An unusual variant of EPAS1 became widespread in Tibetans after they moved onto the high-altitude plateau several thousand years ago. This variant allowed them to survive despite low oxygen levels at elevations of 4,500 meters or more. “We have very clear evidence that this version of the gene came from Denisovans. This shows very clearly and directly that humans evolved and adapted to new environments by getting their genes from another species,” said Prof Rasmus Nielsen of the University of California, Berkeley, who is the senior author of a paper published in the journal Nature." http://www.nature.com/nature/journal/v5 ... 13408.html
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Re: Miceta et al 2013 - Myoglobin Evolution Paper

Postby AlgisKuliukas » Mon Sep 01, 2014 8:32 am

DDeden wrote:Were data on Sea Otters (California) and Marine Otters (Peru) included? Were both freshwater manatees and marine dugongs included in the study?



I don't think so.

DDeden wrote:
Apparently Marine Iguanas (Galapagos) compared to desert and jungle iguanas, as well as sea snakes and hypothetically extinct ichthysaurs, all being reptiles, were excluded, unfortunately.

It seems that both Endurance Running and Endurance Diving in ancient Hominins are not well demonstrated by data.



Yes and it's not good for the sneering response to Elaine's points about elephants having a more aquatic past either.

DDeden wrote:
Are ancient Neanderthal or Denisovan genomes indicative of higher myoglobin capacity compared to modern AMH Hss? Possibly the advent of boating in the last 50,000 years may have reduced selection for apnea in Hss. as has massive selection for lowland agriculture more recently.



No data in the paper on Hsn or Denisovans.

DDeden wrote:
Note a recent article in Nature showing that Tibetans with oxygen hemoglobin hypoxia resistance have Denisovan genes active: "An unusual variant of EPAS1 became widespread in Tibetans after they moved onto the high-altitude plateau several thousand years ago. This variant allowed them to survive despite low oxygen levels at elevations of 4,500 meters or more. “We have very clear evidence that this version of the gene came from Denisovans. This shows very clearly and directly that humans evolved and adapted to new environments by getting their genes from another species,” said Prof Rasmus Nielsen of the University of California, Berkeley, who is the senior author of a paper published in the journal Nature." http://www.nature.com/nature/journal/v5 ... 13408.html


Interesting.
Waterside hypotheses of human evolution assert that selection from wading, swimming and diving and procurement of food from aquatic habitats have significantly affected the evolution of the lineage leading to Homo sapiens as distinct from that leading to Pan. (p118)
Kuliukas, A., Morgan, E. (2011). Aquatic scenarios in the thinking on human evolution: What are they and how do they compare?. In: Vaneechoutte, M., Verhaegen, M., Kuliukas, A. (2011). Was Man More Aquatic in the Past?
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