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"Well, there is help on the horizon and anyone
seriously interested in color genetics should take
a look at Linda Rubin's book: COCKATIEL
GENETICS MADE EASY! Though this book is
primarily directed to breeders of cockatiel
mutations, there is enough information in this
volume to teach anyone the secrets of dealing
with recessive, sex-linked, and dominant
mutations. Click to read rest of review
- Dr. Rainer R. Erhart, American Cage Bird Magazine,
Volume 65, No. 12. p. 37.
seriously interested in color genetics should take
a look at Linda Rubin's book: COCKATIEL
GENETICS MADE EASY! Though this book is
primarily directed to breeders of cockatiel
mutations, there is enough information in this
volume to teach anyone the secrets of dealing
with recessive, sex-linked, and dominant
mutations. Click to read rest of review
- Dr. Rainer R. Erhart, American Cage Bird Magazine,
Volume 65, No. 12. p. 37.
| Excerpt From Chapter 10 Combining Autosomal Multi-recessive Mutations |
a Whiteface/Pied, and instead of writing ww np, we've eliminated the "n" to avoid adding to the
confusion. This would beccome even more apparent when crossing multi-recessive mutations,
which we will be doing in future examples.
Our goal here is to simplify charts as much as possible, therefore it is always best to use the most
direct means whenever feasible. This includes our gene letters. What if, instead, we diagram our
Whiteface male as simply "ww", and diagrammed our Whiteace/Pied hen as "w wp". How did we
arrie at these gene letters?
Remember, we stated that each chromosome has an address site, or home, (i.e., locus) for only
one gene for a particular trait. For example, when we worked with sex-linked genes we could only
have one gene for Lutino on each of the "X" chromosomes, i.e.:
XL XL NOT XLL XN
We may take a similar view of autosomes (remember, autosomes are chromosomes which are
not sex-linked). We will not assign our autosome model "r", with more than one gene of the same
kind (i.e., the same allelic form of a gene).
When we use our training "r"s in place of an "X", we are better able to understand where to put our
genes, and so may not make any errors. Therefore:
rw rw = more easily demonstrates a visual Whiteface
(having double quantities of "w"). And,
rw rwp = is understood as a Whiteface/Pied
(having double quantities of Whiteface, and
only a single quantity of Pied).
Notice that we did not put two of the same recessive genes together on the "r" autosomes (e.g.,
rww rp). We can put any number of recessives on our training "r"s however, we can not put
double quantities on the SAME "r"!
Therefore, let us now use our new recessive model, with the training "r"s and set up our genes as
discussed above:
Example: Whiteface cock X Whiteface/Pied hen
confusion. This would beccome even more apparent when crossing multi-recessive mutations,
which we will be doing in future examples.
Our goal here is to simplify charts as much as possible, therefore it is always best to use the most
direct means whenever feasible. This includes our gene letters. What if, instead, we diagram our
Whiteface male as simply "ww", and diagrammed our Whiteace/Pied hen as "w wp". How did we
arrie at these gene letters?
Remember, we stated that each chromosome has an address site, or home, (i.e., locus) for only
one gene for a particular trait. For example, when we worked with sex-linked genes we could only
have one gene for Lutino on each of the "X" chromosomes, i.e.:
XL XL NOT XLL XN
We may take a similar view of autosomes (remember, autosomes are chromosomes which are
not sex-linked). We will not assign our autosome model "r", with more than one gene of the same
kind (i.e., the same allelic form of a gene).
When we use our training "r"s in place of an "X", we are better able to understand where to put our
genes, and so may not make any errors. Therefore:
rw rw = more easily demonstrates a visual Whiteface
(having double quantities of "w"). And,
rw rwp = is understood as a Whiteface/Pied
(having double quantities of Whiteface, and
only a single quantity of Pied).
Notice that we did not put two of the same recessive genes together on the "r" autosomes (e.g.,
rww rp). We can put any number of recessives on our training "r"s however, we can not put
double quantities on the SAME "r"!
Therefore, let us now use our new recessive model, with the training "r"s and set up our genes as
discussed above:
Example: Whiteface cock X Whiteface/Pied hen
Notice that we move the numbers and their genes in the exact same manner as we have done in previous chapters. We merely use the training "r"s as a device on
which to position our (autosomal) recessive genes, much in the same manner as we used our "X" sex chromosome to position our sex-linked genes.
The beaut of this unconventional method is that we are able to put our recessive genes in their proper places, then "drag" them along 'for the ride' in order to calculate
our answer.
Now, let's look at what we have produced and translate the colors and persentages for the above example:
Remember, any double quantity (e.g., "ww") will be visual for that mutation, and any single quantity (e.g., "p") will be (heterozygous) split for that mutation.
We find that we produce all Whiteface in the above pairing, and that 50% of the offspring will also be split (heterozygous) to Pied. We also assume that in the long run
the number of males to females will be an even 50/50 division.
Before we try another example, let us first look at some autosomal recessives in single and double quantities and see if we fully understand them. Each of the genes
will be diagrammed temporarily on their "training r's" so you will understand how we will be working with them in the short term: ... to learn more, order here
rw rw
rw rwp
rw rw
rw rwp
rw rwp
rw rw
rw rwp
r w rw rw rwp r1 r2 r3 r4
r1 r3
r1 r4
r2 r3
r2 r4
r1 r4
r2 r3
r2 r4
rw rw
rw rwp
rw rw
rw rwp
rw rwp
rw rw
rw rwp
50% Whiteface and
50% Whiteface/Pied
50% Whiteface/Pied
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| Premiere Book Review by Dr. Rainer R. Erhart |
