History of sheep

Scientists have used the vestiges of ancient retroviruses to unravel the history of sheep domestication,

Specialised wool production began in South-west Asia, while other findings imply some truth behind a tale in the Bible, say the international team of researchers, led by scientists from the University of Glasgow.

Sheep were first domesticated 11 000 years ago in South-west Asia before spreading to Europe and the rest of the world. Initially, they were first selected for their meat and eventually also for secondary products like wool.

One study used a family of endogenous retroviruses as markers to deduce the genetic lineage of 133 breeds of domestic sheep from various locations around the world.

Endogenous retroviruses integrate their DNA into the genetic code of the host they infect, enabling scientists to detect the remnants of ancient infections caught by sheep and their ancestors.

By testing for the presence of a particular set of retroviruses, known as enJSRVs, and comparing their prevalence in each breed of sheep, the researchers were able to distinguish primitive breeds of sheep from more recently domesticated ones.

The results support the theory that the breeding of sheep for wool and other secondary products began in South-west Asia, before spreading to Europe through secondary migrations.

Matching the retrovirus signatures with the location of the sheep, they gained insight into ancient migration routes. For example, Orkney sheep  (left) were found to be closely related to breeds in Scandinavia, while the Soay sheep (top) of St Kilda, Scotland, have links to the Mediterranean Mouflon. 

Intriguingly, they also found that the Jacob sheep (left)  of the British Isles is more similar to South-west Asian and African breeds than other British sheep. The breed is named  after the Biblical story of Jacob, who is said to have taken "every speckled and spotted sheep" as a wage from his father-in-law, Laban. The note in the book of Genesis is possibly the first recorded use of selective breeding.

Wool clothes

Wool has all the right messages to appeal to discerning consumers. It is naturally sustainable, biode-gradable, resilient and improves indoor air quality through the absorption of harmful gases. Furthermore, it is non-allergenic, soft and natural, flame retardant, and offers an incredible range of colour and style opportunities.

Process for making wool clothes

Worsted yarn uses only the best fleece from the back of the sheep. It is the longest, strongest and richest in lanolin. The fibres are combed to lie flat and spun in "two ply’s" that when spun together creates a "3 diameter run" piece of yarn. It looks much neater and tighter on a spool than woollen yarn. Since worsted yarn’s fibres are fairly uniform in length there are no short pieces to fail or cause that scratchy feeling. It is considered a stronger fabric.

Woollen yarn on the other hand is spun from all the various lengths of wool fibres found on a sheep’s body, both long and short fibres from the sheep’s back, belly, bottom, legs etc. Since it is not combed to lie flat, woollen yarn has a fuzzy look because the shorter fibre ends stick out of the yarn imparting a dull appearance to the finished product. Clothes of woollen yarn will usually feel rougher or scratchier.

Types of wool yarns

Woollens: A general term describing various fabrics woven from woollen yarn. Woollen yarn is spun from the shorter wool fibres, which are not combed to lie flat as in worsted yarn. Soft surface textures and finishes are produced and the weave of individual yarns does not show as clearly as in worsted fabrics. Woollen fabrics include tweeds, fleeces and meltons.

Worsteds: A general term describing various fabrics woven from worsted yarns containing the longer fibres spun from combed wool. Only the prime, longer fleece is used to produce worsted fabrics. Worsted wool refers to tightly woven, smooth, clear finished goods in a variety of twill and other stronger weaves.

The wool for clothing is spun using the worsted process. It is spun into a single piece of yarn and then two pieces of yarn are twisted together making a 2 ply yarn strand. The 2 ply is then twisted together, making what is called 2/18 diameter yarn. Four pieces of yarn are then woven into the cloth.