DNA’s going round the twist
QUESTION DNA is represented as a spiral. Is this a rare form of the molecule?
PICTURES of the double helix of deoxyribonucleic acid ( DNA) have become so common that we are all familiar with its shape and structure.
This classic form of a right-handed, double-twisted string with interlinking parts, discovered by biologist James Watson and physicist Francis Crick in 1953, is called B-DNA.
However, this idealised shape is unlikely to exist within the cells of living organisms. There is simply not enough room for the DNA to be stretched out in a perfect, linear form. From simple bacteria through to complex cells, the DNA must be compacted by more than a thousandfold to fit inside the cell or nucleus.
Two other rare biologically active DNA molecules are A-DNA and Z-DNA. A-DNA exists only in the dehydrated state and differs from the B form in that it is a 20degree rotation rather than 36 degrees. Z-DNA is found where DNA is being copied. The helix winds to the left in a zigzag — hence its name.
Carsten Jessen, Birmingham.
QUESTION How did Richard de Clare, Earl of Chepstow, earn his nickname of Strongbow?
NICKNAMES were common among the Anglo-Norman nobility and often related to a physical characteristic, such as Rufus (ginger hair), or manner of dress, such as Courtmantle (short cloak). We can only imagine the antics of Roger Deus Salvet Dominas (‘God save the ladies’)!
An alarming number of aristocrats were wounded or killed by arrows while taking part in their favourite pastime of deer and boar chases in woodland.
At an early age, they would begin to train in archery using a relatively weak bow. Richard FitzGilbert de Clare (1130 to 1176) may have inherited the nickname Arc-fort (Strong Bow in Anglo-Norman) from his father, Gilbert (1100-48), who as a child may have tried to use a bow that was too powerful for him. There is no surviving account to explain how or when the nickname was first applied, leading to fanciful modern speculation.
Gilbert and Richard each held the lordship of Netherwent (Gwent Is Coed), Monmouthshire, whose men, according to the claim of historian Catherine Armstrong, ‘were known for their skill and use of an unusually long and strong bow’.
However, this is not quite true, according to Gerald of Wales. As a clerk to Henry II and two archbishops, he travelled throughout the country during the latter part of the 12th century.
He wrote in 1191 that the men of Gwent were more skilled archers than those from other parts of the country. ‘ The bows they use are not made of horn, or of sapwood, nor yet of yew,’ he said.
‘The Welsh carve their bows out of the dwarf elm trees in the forest. They are nothing much to look at, not even rubbed smooth, but left in a rough and unpolished state. Still they are firm and strong.
‘You could not shoot far with them, but they are powerful enough to inflict serious wounds in a close fight.’
It would be impossible to make an ‘unusually long bow’ from a dwarf elm!
There are several images of Welsh bows in the 13th-century manuscript the Littere
Wallie, which shows them to be short and knobbly — exactly like Gerald of Wales’s description. The late medieval longbow used in advertising for a certain brand of cider is not linked to Welsh short bows or the 5ft English bows of the 12th century.
David Rayner, Canterbury, Kent.
QUESTION Why do we ‘turn the air blue’ when swearing?
THE origin of the word ‘blue’ in the sense of lewd, coarse or pornographic is something of a mystery.
John Mactaggart’s Scottish Gallovidian Encyclopedia in 1824 gives an early example: ‘Thread o’Blue’ to mean “any little smutty touch in song- singing, chatting or piece of writing.”’ No evidence is given to explain why.
London book collector John Camden Hotten suggested in his A Dictionary Of Modern Slang, Cant And Vulgar Words, in 1859, that the connotation had its origins in the French Bibliotheque Bleue.
This series of books were published between the early 17th and mid-19th centuries on low-quality paper with a blue cover. The Oxford English Dictionary disputes this, ‘since such material appears in general to have been highly moral in tone’. The books were not lewd and were popular with all social classes.
In 1890’s Slang And Its Analogues Past And Present, John Stephen Farmer and William Ernest Henley suggested this definition of blue may be connected to the blue gown worn by a convicted prostitute in a house of correction. That usage dates from the 16th century and doesn’t seem to have lasted into the 1800s.
A related possibility is the colour’s association with uniforms worn by servants and licensed beggars, paralleling the evolution of the term ‘ blue collar’, which means manual labour.
An alternative derivation comes from ‘talking a blue streak’, which means to be voluble or garrulous, speak rapidly, continuously and at great length. The term probably stems from the blinding speed and vividness of a lightning flash.
A ‘ blue streak of oaths’ (swearing) dates from 1847 in The Knickerbocker, or New-York Monthly Magazine.
Jon Baldwin, King’s Lynn, Norfolk.
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