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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 6 Charting Sex-linked Mutations |
In chapter three, we learned the notation for writing and interpreting sex-linked
mutations. Armed with this information, we are now ready to chart these sex-linked
mutations by working with a slightly modified graph as shown below:
mutations. Armed with this information, we are now ready to chart these sex-linked
mutations by working with a slightly modified graph as shown below:
Sire's Chromosome Pair Dam's Chromosome Pair
Pairing #1: Male Offspring Pairing #3: Female Offspring
Pairing #2: Male Offspring Pairing #4: Female Offspring
We may also use our subscript numbers once again, as a learning aid to the above graph,
merely to demonstrate how the sex chromosomes pair off:
___X1 X2 X3 X4
X1 X3 X1 X4
X2 X3 X2 X4
You may also "feel" the familiar technique of the FOIL method we learned in the previous
chapter. However, as we will be charting the sex-linked colors somewhat out of order
(compared to the recessive graph you learned in the previous chapter), the FOIL method will
also differ somewhat in this chapter. Yet, it will be easier for you later on, if you learn to complete
the left (male) side of the diagram, before going on to complete the right (female) side. This will
be expalined as we progress through the chapter.
We will initially demonstrate both the subscript numbers, and the FOIL technique (to check your
work) in this chapter, until with enough practice you no longer need to rely upon them.
In chapter two, we listed seeral assumptions under the "Golden Rules," which we
will prove throughout this chapter. You may refer back to chapter two for additional information as we cover them however, the major points are repeated here for your
convenience.
I. NORMAL GREY X MUTATION MATINGS
Let's start by charting a Normal Grey cockatiel with the sex-linked Lutino mutation. Remember, now that we are working with sex-linked mutations, it is imperative to
identify the gender of each carrier of a mutation. In other words, we need to know the sex of the parent who is affected by one or more sex-linked mutations.
Example: NORMAL GREY COCK X LUTINO HEN
F O I L
XN XN XL Y X1 X2 X3 Y4
XN XL XN Y X1 X3 X1 Y4
XN XL XN Y X2 X3 X2 Y4
The above graph utilizing numbers shown at right will help you to move each "X" and "Y" chromosome to their proper position. You will note how each chromosome is
assigned a number to illustrate where it is to be placed on the completed graph at left.
In addition, the letters of the acronym "FOIL" are positioned on top of the graph with numbers to aid you with checking your work below. Each letter of the acroym (i.e., F. O.
I. L. ) shown on the graph stands for the first letter representing the position of First, Outer, Inner, and Last. Also, each quadrant (upper and lower, right and left) is now
identified.
You will note a slight modification in the FOIL method given below, between steps two and three which are now inversed. The inversed steps are underlined to show how
they differ from what you've learned in the preceding chapter. ... to learn more, order here
convenience.
I. NORMAL GREY X MUTATION MATINGS
Let's start by charting a Normal Grey cockatiel with the sex-linked Lutino mutation. Remember, now that we are working with sex-linked mutations, it is imperative to
identify the gender of each carrier of a mutation. In other words, we need to know the sex of the parent who is affected by one or more sex-linked mutations.
Example: NORMAL GREY COCK X LUTINO HEN
F O I L
XN XN XL Y X1 X2 X3 Y4
XN XL XN Y X1 X3 X1 Y4
XN XL XN Y X2 X3 X2 Y4
The above graph utilizing numbers shown at right will help you to move each "X" and "Y" chromosome to their proper position. You will note how each chromosome is
assigned a number to illustrate where it is to be placed on the completed graph at left.
In addition, the letters of the acronym "FOIL" are positioned on top of the graph with numbers to aid you with checking your work below. Each letter of the acroym (i.e., F. O.
I. L. ) shown on the graph stands for the first letter representing the position of First, Outer, Inner, and Last. Also, each quadrant (upper and lower, right and left) is now
identified.
You will note a slight modification in the FOIL method given below, between steps two and three which are now inversed. The inversed steps are underlined to show how
they differ from what you've learned in the preceding chapter. ... to learn more, order here
FOIL METHOD
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| Premiere Book Review by Dr. Rainer R. Erhart |
