- The principal component of hair is a protein molecule called keratin. All protein molecules consist of long chains of small molecular units, the amino acids, of which there are 20 different kinds. Each keratin molecule in hair consists of many hundreds of amino acid units, arranged in an irregular order, although not a random one by analogy, the letters in this sentence are in an irregular order, but the sentence has meaning. The order in keratin determines how the molecules fit together, giving the hair strength and flexibility. more »
- Wool fiber: Like all other protein fibers, wool is also derived from the animal hair. Wool is mainly used as a minor blend (up to 10%) with cotton to introduce special properties to the terry fabric. Raw wool contains a wide variety of impurities, which can account for between 30% and 70% of the total mass. The impurities consist of wool grease, secreted from the sebaceous glands in the skin; suint, produced from the sweat gland; dirt and sand. Wool grease consists chiefly of esters, formed from a combination of sterols and aliphatic alcohols with fatty acids. Suints consist primarily of the potassium salts of organic acids. more »
- As mentioned, simply-inherited and polygenic traits are equally subject to the same Mendelian and non-Mendelian inheritance forces. And both can have gene and genotypic frequencies shifted by selection and mating systems. But while it is often straightforward to observe the effect of a simply-inherited trait owing to the small number of genes involved, this isn’t the case with polygenic traits. It is often not even known how many genes are involved in a particular polygenic trait, nor what the effect of each may be. It is because of this complexity that breeders must take very different approaches when working with simply-inherited and polygenic traits. more »
- While — for the most part — there are differences between simply-inherited and polygenic traits, they also share much in common. Both types of trait are still determined by genes and inheritance. more »
- The word trait, you may recall, is often used interchangeably with phenotype, but they are not the same thing at all. A trait is something that can be measured or observed, for example temperament, colour or wool staple length/year. A phenotype is the value of the trait: ‘aggressive’, ‘brindle’ or ‘120mm’. Traits fall into two categories: simply-inherited and polygenic. more »