120
No Cla t fo ssr r o Us om e
What Genotype Has That Cat?
PR E V ON IEW LY
Consult the table of genes listed on the previous pages and enter the allele symbols associated with each of the phenotypes in the column headed 'Allele'. For this exercise, study the appearance of real cats around your home or look at colour photographs of different cats. For each cat, complete the checklist of traits listed below by simply placing a tick in the appropriate spaces. These traits are listed in the same order as the genes for wild forms and mutant forms on page 118. On a piece of paper, write each of the cat's genotypes. Use a dash (-) for the second allele for characteristics that could be either heterozygous or homozygous dominant (see the sample at the bottom of the page). NOTES:
1. Agouti fur colouring is used to describe black hairs with a light band of pigment close to its tip. 2. Patches of silver fur (also called chinchilla) produces the silver tabby phenotype in agouti cats. Can also produce "smoke" phenotype in Persian long-haired cats, causing reduced intensity of the black. 3. Describes the dark extremities (face, tail and paws) with lighter body (e.g. Siamese). 4. The recessive allele makes black cats blue-grey in colour and yellow cats cream. 5. Spottiness involving less than half the surface area is likely to be heterozygous.
Phenotype Record Sheet for Domestic Cats
Gene
Agouti colour
Pigment colour
Phenotype
Allele
Sample
Cat 1
Cat 2
Cat 3
Cat 4
Agouti1
Non-agouti Black
Brown
Unicoloured
Silver patches2
Colour present
Pointed3
Albino with blue eyes Albino with pink eyes
Ear shape Hairiness
Hair length Tail length
Orange colour
Number of digits Hair curliness
Dense pigment
Dilute pigment4 Pointed ears Folded ears
Normal, full coat Hairlessness Short hair Long hair
Normal tail (long)
Stubby tail or no tail at all
Normal colours (non-orange) Orange
Normal number of toes
Polydactylism (extra toes) Normal, smooth hair Curly hair (rex) No white spots
Spottiness
White spots (less than half)5
White spots (more than half)
Stripes
White coat
Mackerel striped (tabby) Blotched stripes Not all white
All white coat colour
Sample cat: (see ticks in chart above)
No Cla t fo ssr r o Us om e
Pigment density
To give you an idea of how to read the chart you have created, here is an example genotype for the author's cat with the following features: A smoky grey uniform-coloured cat, with short smooth hair, normal tail and ears, with 5 digits on the front paws and 4 on the rear paws, small patches of white on the feet and chest. (Note that the stripe genotype is completely unknown since there is no agouti allele present)
GENOTYPE:
aa B– C– dd fdfd Hr– ii L– mm oo pdpd R– Ss ww
© Biozone International 2006
Code: A 3
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