Grazie per i 25 anni..., me li sento, ma la carta d'identità dice altro...(questo, alcuni dicono, non è un forum per vecchi...ma vedo che però non mancano gli ultra40enni...).
Una bella sintesi di quanto vado affermando l'ho trovata qui:
http://en.wikipedia.org/wiki/Blond
In particolare:
Natural lighter hair colors occur most often in Europe and less frequently in other areas.[21] In northern European populations, the occurrence of blond hair is very frequent. The hair color gene MC1R has at least seven variants in Europe giving the continent a wide range of hair and eye shades. Based on recent genetic information carried out at three Japanese universities, the date of the genetic mutation that resulted in blond hair in Europe has been isolated to about 11,000 years ago during the last ice age.[22]
A typical explanation found in the scientific literature for the evolution of light hair is related to the requirement for vitamin D synthesis and northern Europe's seasonal deficiency of sunlight.[23] Lighter skin is due to a low concentration in pigmentation, thus allowing more sunlight to trigger the production of vitamin D. In this way, high frequencies of light hair in northern latitudes are a result of the light skin adaptation to lower levels of sunlight, which reduces the prevalence of rickets caused by vitamin D deficiency. The darker pigmentation at higher latitudes in certain ethnic groups such as the Inuit is explained by a greater proportion of seafood in their diet. As seafood is high in vitamin D, vitamin D deficiency would not create a selective pressure for lighter pigmentation in that population.
Non saprei cosa aggiungere se non appunto la recente scoperta che la vit.D3 è contro il tumore della prostata e quindi poteva servire a questi nostri antenati sintetizzarla una volta vestiti da da piedi a collo[
] (superfluo aggiungere che le donne non hanno la prostata...).
Ciao
MA - r l i n
Una bella sintesi di quanto vado affermando l'ho trovata qui:
http://en.wikipedia.org/wiki/Blond
In particolare:
Natural lighter hair colors occur most often in Europe and less frequently in other areas.[21] In northern European populations, the occurrence of blond hair is very frequent. The hair color gene MC1R has at least seven variants in Europe giving the continent a wide range of hair and eye shades. Based on recent genetic information carried out at three Japanese universities, the date of the genetic mutation that resulted in blond hair in Europe has been isolated to about 11,000 years ago during the last ice age.[22]
A typical explanation found in the scientific literature for the evolution of light hair is related to the requirement for vitamin D synthesis and northern Europe's seasonal deficiency of sunlight.[23] Lighter skin is due to a low concentration in pigmentation, thus allowing more sunlight to trigger the production of vitamin D. In this way, high frequencies of light hair in northern latitudes are a result of the light skin adaptation to lower levels of sunlight, which reduces the prevalence of rickets caused by vitamin D deficiency. The darker pigmentation at higher latitudes in certain ethnic groups such as the Inuit is explained by a greater proportion of seafood in their diet. As seafood is high in vitamin D, vitamin D deficiency would not create a selective pressure for lighter pigmentation in that population.
Non saprei cosa aggiungere se non appunto la recente scoperta che la vit.D3 è contro il tumore della prostata e quindi poteva servire a questi nostri antenati sintetizzarla una volta vestiti da da piedi a collo[
] (superfluo aggiungere che le donne non hanno la prostata...).Ciao
MA - r l i n