Link to Abbreviations
1B&B p 175 ¶ 3. 4. Heteroygous whites.
2homoygous - an allele occurring twice ie 'WW'.
heteroygous - an allele occurring only once ie 'Ww'.
3B&B p 172 ¶11. Original breeding stock.
4B&B p 173 ¶ 2. Definition of white.
5(B&B) Bergsma and Brown. White Fur, Blue Eyes and Deafness in the Domestic Cat. Journal of Heredity 1971 62 pp 170 - 185.
6(GCB) Robinson, Roy. Genetics for Cat Breeders, 3rd Edition 1991 Pergamon Press.
7(PT) Blue Eyes White Fur and Deafness. Patricia Turner 1995.
8B&B p 176 ¶ 6. Lateral correlation.
9unilateral - one eye blue or one ear deaf.
bilateral - both eyes or both ears the same.
10phenotype - outward appearance or observable characteristics.
genotype - genetic makeup.
11tapetum lucidum - the reflective layer behind cat's retinas which causes the 'cat's eyes' shine. Also referred to as a 'tapetum' or 'tapetums'.
12B&B p 180 ¶ 4. No correlation between eyes and hearing.
13polygenes - more than one gene contributing to a variable genetic effect. Major genes like the silver 'I' gene or the blue 'dd' genes follow predictable rules, for instance one 'I' gene or two 'd' genes always produce a silver or blue cat respectively. Polygenetic effects do not follow simple rules or tend to vary, sometimes from full to no appearance. These polygenes usually cause dismay to the researcher as they are so difficult to pin down or even describe.
14B&B p 177 ¶ 3. Blue eye genes recessive or additive.
15locus - the 'home base' of a gene. Like Levis, genes come in pairs, one from mum and one from dad. Both genes have their own locus where all the 'alleles' or variants of the gene are to be found. Two alleles can be shown to share a locus if they displace each other, in other words an animal heteroygous ref 2 for one allele cannot pass on the other allele to its progeny.
16segregation ratio - proportions of offspring with different inherited characteristics. For instance, whites x whites (Ww x Ww) give 1 WW : 2 Ww : 1 ww and thus a segregation ratio of 3 whites : 1 coloured.
17dominant - only one gene written as a capital letter is needed to show the effect.
recessive - two genes written as small letters are needed to show the effect.
18B&B p 175 ¶ 3. White homoygous cats are more blue and more deaf.
19penetrance - whether a gene actually manifests itself or not. An impenetrant gene fails to show up, even when it is known to be present.
incomplete dominance - a gene sometimes does not follow the rules.
expressivity - the degree to which a variable gene shows up in the phenotype. ref 10
20PT p 1 ¶ 1. 'Turner' or oriental blue eyes are not associated with deafness.
21B&B tables pp 176 - 178. Incidences of blue eyes and deafness.
22B&B p 177 ¶ 1-2. Blue eyes carried by coloured cats.
23GCB p 125 ¶ 2 Foetal development of spotting patches.
24B&B p 174 ¶ 5-6; p 182 ¶ 4-5. 'W' and 'S' have the same locus ref 15. They suggest that the 'S' gene should be referred to as 'WL', 'WH', and 'WT', for low grade spotting, high grade spotting and totally white respectively. In fact there are a large number of gradations of white between 100% and 0% and the choice of grades of spotting is somewhat arbitrary, considering these are most likely under the control of polygenes. However, the all-white 'WT' gene looks as if it is a distinct allele from the 'S' series.
25GCB p 124 ¶ 4. Gloving gene.
26GCB p 124 ¶ 3. Medallion gene.
27oriental blue (small 'o') - Siamese type deep blue eyes.
occidental blue (small 'o') - Persian type pale blue eyes.
28PT p 2 ¶ 4. Deaf Foreign Whites.
29PT p 2 Incidence of deafness.
30FIFe General Assembly, Prague, May 1994. Proposal 6 by Mundicat to forbid white x white crosses. The proposal was lost.
31GCB p 185 ¶ 1 Acceptable percentage of 1%
32alleles - alternative forms of a gene.
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B&BBergsma and Brown, ref 5
GCBGenetics for Cat Breeders, ref 6
PTPatricia Turner. ref 7
C AFelis Britannica, the British Member of FIFe
FIFe The Fédération Internationale Féline
EMSFor more information click on The FIFe EMS codes Explained.