Mendelian laws re-examined

"Susan Lolle, Robert Pruitt and their colleagues have shown that a significant percentage of a watercress Arabidopsis) plant's 'grandchildren had genetic information identical to that of the grandparent, but not the parent, and postulate that the “lost” genetic information resides outside the standard genome and is only retrieved when it may be beneficial.

The information was not lost, but rather “hidden” from scientists.'

From Science Daily, 28 Mar 2005. See also the earlier Wired news article.

The Kakapo breeds

I first heard of the sad story of this strange bird from New Zealand, the kakapo (Strigops habroptilus), in Douglas Adams and Mark Carwardine's (radio series and) book Last Chance to See.

The kakapo, the heaviest parrot in the world (up to 4kg), seemed doomed by its strange breeding habits and the deadly effects of man's intrusion on the islands. The population was whittled down to a mere 50 known individuals by 1995. Their extinction seemed inevitable until a recovery programme was initiated. Now up to 86, there was more good news last week - the kakapo are breeding again and three chicks have been born!

See: Breeding success for rare kakapo. By Kim Griggs, BBC News, 26 Mar 2005. And check the Kakapo Recovery Programme for latest news.

A blog, Another Chance to See tracks the species mentioned in "Last Chance to See" honour of the late Douglas Adams.

Evolution of swimming at deeper depths

The root effect haemoglobin, which allows fish to use oxygen in the blood to inflate the swim bladder, appeared to have evolved only once in the evolutionary history of fishes. Possessing this protein allowed the formation of blood vessels which supported the retinas of fishes and allowed them to see better.

According to Berenbrink et al, this network of veins and arteries, called the rete mirabile, also appeared to have evolved only once about 250 million years ago. Swimbladders on the other hand, evolved independently in 4 fish groups, this could account for the diversity of fishes we see today.

"Fish Diversity Tied to Evolution of Diving Ability." By Sarah Graham. Scientific American Science News, 21 Mar 2005, reporting on Berenbrink, M. P. Koldkjær, O. Kepp & A. R. Cossins, 2005. Evolution of Oxygen Secretion in Fishes and the Emergence of a Complex Physiological System. Science, 18 March 2005: 1752-1757.

Who's at risk during stopovers - the heavy or light bird?

Dierschke, V., 2003. Predation hazard during migratory stopover: are light or heavy birds under risk? Journal of Avian Biology, 34 (1): 24-29.

This is a useful reminder that there are no "obvious answer" until the parameters relevant to the specific site are examined. Singapore's mudflats for example, has a marked absence of predators.

And over the route of a migratory bird, a different combination of factors apply at each stopover. These days at least, adaptive responses to habitat loss surely supersedes other factors.

Abstract - On the offshore island Helgoland, passerine birds killed by predators (feral cats Felis catus and raptors, mainly sparrowhawks Accipiter nisus) during stopover were measured and weighed when found freshly killed and still intact. Supplemented by data of migrating birds ringed on Helgoland and predated on the island later on, age and body mass of victims were compared to live birds trapped on Helgoland during ringing operations.

In the eleven species considered, most predator kills fell within the lightest 20% of birds measured during ringing, regardless of which type of predator was involved.

It seems that the risk of being heavy due to fuel loads with respect to reduced escape performance is overestimated. The higher exposure of light birds due to more intense foraging and displacement to suboptimal habitats is probably of higher biological significance by offering conspicuous prey for predators.

The lower risk of heavy birds when prey of different body condition is available for predators has implications for modelling optimal migration behaviour, and predation risk is perhaps not an important factor for migrants when deciding on site use.

Homo floriensis microcephaly scotched

LB1 is the first female skeleton discovered at the Liang Bua site, reported in October 2004 and described as Homo florisiensis.

After the discovery, several researchers hadsuggested that the remains were really those of a modern human (Homo sapiens), probably a pygmy with the brain defect known as microcephaly

Paul Rincon of BBC News reports "Hobbit was 'not a diseased human'" based on the article "The Brain of LB1, Homo floresiensis" in Science that was just published online (03 Mar 2005).

"The overall shape of LB1's the brain resembles Homo erectus (an earlier ancestor of modern humans) more than anything else. But it's its own thing," said Dean Falk, the corresponding author of the study.

"It has some very advanced features that harken towards [modern] humans. Those features are at the frontal lobe, the temporal lobes at the sides and at the back of the brain. In our opinion, LB1 is not in any way, shape or form, a true microcephalic."

Flores hominid bones returned

"After a contentious sojourn in the lab of a senior Indonesian paleoanthropologist, most of the ancient hominid bones from the Indonesian island of Flores, published to acclaim in Nature last fall, are back in a new secure storage facility at their home institution, the Centre for Archaeology in Jakarta.

Two leg bones from LB1, the 17,000-year-old type specimen nicknamed "The Hobbit" because it is so tiny, were left behind for additional study."

'Jean-Jacques Hublin, of the Max Planck Institute for Evolutionary Anthropology in Leipzig, said Jacob [Teuku Jacob, professor emeritus of paleoanthropology of Java's Gajah Mada University], has been treated unfairly.'

"The way it's presented in most of the media is that a group of scientists has made a fantastic discovery, and this discovery has been 'stolen' by an old Indonesian scientist. "I do believe it's a case of Western arrogance."

See: Flores hominid bones returned. By Tabitha M Powledge, The Scientist, 28 Feb 2005.