Slide 1
How to make a chocolate rabbit Basics of the dominant/recessive
relationship
A review of basic genetic termsRabbit colors, just like other
traits (size, fur structures, eye color, toenail color, and
hundreds of others) are inherited from the rabbit's parents: called
the Sire and Dam.
The recipe for chocolate rabbits The nucleus (center) of every
cell (muscle, blood, skin, hair, etc) contains all the information
that determines the genotype of the rabbit. The genotype is similar
to a set of instructions. It's just like a recipe so we can say the
recipe is carried in the genes, which are certain spots on the
chromosomes, in the nucleus of each cell.
Major Ingredients Rabbits have 22 pairs of chromosomes. Each
chromosome has lots and lots of genes-hundreds, maybe thousands.
Every cell of every part of the rabbit has 22 pairs of
chromosomes.
Out of the thousands of genes in a rabbit, the major genes for
colors have been identified by scientists. These are the dominant
genes
A for agouti patternB for blackC for having colorD for density
of colorE for extension of color along the hair shaft.
The Secret IngredientVery rarely, a gene changes, or mutates,
for some unknown reason, and it will take a different form. Another
form of a gene is called an allele. A rabbit with a mutated gene
can pass this new allele to its offspring. The scientists have
identified recessive alleles of the 5 dominant color genes (A, B,
C, D, E) and have given them lower-case letters to serve as their
genetic codes (a, b, c, d, e).
a for absence of agouti pattern, making it solidb for brown
(chocolate, actually)c for no color (albino)d for dilutee for
non-extension of color on the hair shaft.
Step oneWhen a male rabbit (buck) and a female rabbit (doe) are
mated, the buck provides the sperm cell, with 22 single
chromosomes, to combine with an egg cell from the doe, with 22
single chromosomes to make 22 pairs for the first cell of the
developing new bunny. The baby bunny gets half of each of its
chromosome pairs from the sire (father) and half from the dam
(mother). SO, since the genes are on the chromosomes, it's getting
half of it's genes from the sire and half from the dam.
How much of each ingredient?Since every bunny inherits half of
each gene pair from its sire and half from its dam, it might
inherit an original gene form (capital letter) from one parent, but
a different form of the same gene (lower-case letter) from the
other parent.We want a chocolate colored rabbit, so the genes we
need from each parent are:a, so its a solid colored rabbit through
all of its fur.b, so it gives us the chocolate color instead of
black.
Results are not always what we want, so we may have to try
againCapital letter codes for the dominant genes and they dominate;
what they say goes! Even when there is one dominant gene and one
recessive gene in a gene pair, the color will be what the dominant
gene says. This is the dominant/recessive relationship.
B series of rabbit coat color
BB dominant blackbb recessive brown (chocolate)
The possibilities
