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PEAFOWL GENETICS
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SEX-LINKS
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CAMEO, PURPLE, OATEN
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Some basics to get us started.
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Each bird carries 2 sex chromosomes which determine if that bird is a male or a female.
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If it is a male it carries 2 'Z' chromosomes, and is referred to as ZZ.
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If it is a female, it has 1 'Z' and 1 'W' chromosome, and is referred to as ZW.
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The Z chromosomes are quite large (for a chromosome) and have room on them to carry lots of
information.
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On the other hand, the W chromosome is tiny, and is only large enough to carry the information
required to make the bird a female.
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These ZZ and ZW chromosomes are carried on each and every cell in the birds' body... with one
exception. The sex cells.
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In the male, the sperm cells carry 1 copy of the Z chromosome.
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In the female, the ova (or egg cell) carries either a Z chromosome or a W chromosome.
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If the egg carries the Z, then that egg will become a male bird.
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If the egg carries the W, then that egg will become a female bird.
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So, as you can see, the females egg cells are pre-destined to be male or female.
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When the 2 cells unite during the mating process, the male will always contribute a Z chromosome.
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Many of you who have studied genetics in high school or college may be thinking....
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Hey, Valerie, this is bass ackwards!
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And, you would be correct.
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It's just the opposite in mammals (including humans)
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The only sex linked peafowl I am aware of are the Cameo, the Purple and any of their combinations.
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By combinations, I mean cameo pied, purple pied, cameo black shoulder (which is an Oaten), etc.
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As I mentioned above, W is tiny and only carries information to make the bird a female.
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Z is large, and carries all the sex-link color information.
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Since the female only has 1 Z chromosome, she only needs one copy for the color to be expressed.
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The male has 2 Z chromosomes, so he will need 2 copies for the color to be expressed.
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Male sex-linked birds are hard to get.
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This first mating will assume that you have a pair of purple peafowl. The male is ZsZs the female is ZsW
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s will refer to either sex-linked color.
Think of 's' as purple or cameo
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I will call it purple.
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100% of the offspring are purple
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Now, let's assume you DON'T have a pair.
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Female purples are much easier to come by, so let's assume you have a purple hen and an India blue cockbird.
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Males:
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Genotype= 100% ZBZs hetero blue
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Phenotype= 100% India blue
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these males carry 1 s gene
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Females:
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Genotype= 100% ZBW India blue
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Phenotype= 100% India blue
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these females have no s gene
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Next, we will do 2 different matings to show the possibilities.
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1) We will mate these siblings together. ZBZs and ZBW
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2) We will mate the original purple hen ZsW (mother) to the male offspring ZBZs
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mother son mating (ZBZs X ZsW)
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brother sister mating (ZBZs X ZBW)
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Males:
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Genotype= 50% ZBZs ZsZs
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Phenotype= 50% blue 50% purple
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50% heterozygous blue (ZBZs)
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50% homozygous purple (ZsZs)
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Males:
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Genotype= 50% ZBZB 50% ZBZs
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Phenotype= 100% India blue
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50% homozygous India blue (ZBZB)
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50% heterozygous India blue (ZBZs)
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Females:
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Genotype= 50% ZBW 50% ZsW
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Phenotype= 50% blue 50% purple
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50% homozygous India blue (ZBW)
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50% homozygous purple (ZsW)
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Females:
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Genotype= 50% ZBW 50% ZsW
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Phenotype= 50% blue 50% purple
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50% homozygous India blue (ZBW)
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50% homozygous purple (ZsW)
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In this mother son mating we have reached out goal.
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We have produced both male and female purples.
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Using the information we have learned on these pages, see if you can create the following:
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OATEN: this is a cameo X black shoulder (sort of)
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Female oaten= ZcWbb
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Male oaten= ZcZbbc
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Purple blackshoulder (no fancy name for this one yet)
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Female= ZpWbb
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Male= ZpZbbp
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Purple Pied:
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Female= ZpWPT
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Male= ZpZpPT
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Cameo pied:
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Female= ZcWPT
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Male= ZcZcPT
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If you come up with ZsZsTT....or a ZsWTT then e-mail me, and I'll tell you what you've got.
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