One other way to illustrate the subject line..
If you have a pea combed bird that lays blue or green eggs. And you cross her with a single combed roo.
IF and that's the important part.. IF the chicks hatch out with both single and pea combs, the chances normally are that the single combed chicks out of this cross will not lay blue or green eggs and the pea combed pullets laying blue or green are "pretty high".
The problem is EE have been outcrossed with other pea combed birds so there ARE pea combed birds floating around in that gene pool that "seem" to break this "rule" but that's just it- those aren't the "birds being talked about with the pea comb plus blue egg gene being linked".
One other example would be let's say you get a pure Araucana pure for the blue egg gene. If you cross her with a RIR, all of the chicks will have pea combs and all pullets will lay blue/green eggs.
The you breed those cross pullets with an Orpington roo, you will get half pea combed and half single combed chicks. Again, normally the pattern will be that all the blue/green egg layers out of this cross will happen to have pea combs.. (all of the single combed pullets out of THIS cross will be laying brown or tan tinted eggs..)
That's an clear example of 'pea comb and blue egg genes being closely linked'. Test mating using birds known to have this or that gene(s) and doing experimental study crosses will bear this out.. again and again. It's proven. It's using the 'mutts'(other words, the birds can be 'goodness knows what they have genetically..) & not understanding the gene crossover that makes this concept seem confusing.
As sonoran said, it's not strictly 100% as a well known genetic process called 'crossing over' can and DO happen and throw the occasional single combed hen that lays blue/green eggs or peacombed hen laying brown eggs.
It's due to this crossing over plus my own selection that most of my blue/green egg layers are single combed. Just a little quirk that delights me..
If you have a pea combed bird that lays blue or green eggs. And you cross her with a single combed roo.
IF and that's the important part.. IF the chicks hatch out with both single and pea combs, the chances normally are that the single combed chicks out of this cross will not lay blue or green eggs and the pea combed pullets laying blue or green are "pretty high".
The problem is EE have been outcrossed with other pea combed birds so there ARE pea combed birds floating around in that gene pool that "seem" to break this "rule" but that's just it- those aren't the "birds being talked about with the pea comb plus blue egg gene being linked".
One other example would be let's say you get a pure Araucana pure for the blue egg gene. If you cross her with a RIR, all of the chicks will have pea combs and all pullets will lay blue/green eggs.
The you breed those cross pullets with an Orpington roo, you will get half pea combed and half single combed chicks. Again, normally the pattern will be that all the blue/green egg layers out of this cross will happen to have pea combs.. (all of the single combed pullets out of THIS cross will be laying brown or tan tinted eggs..)
That's an clear example of 'pea comb and blue egg genes being closely linked'. Test mating using birds known to have this or that gene(s) and doing experimental study crosses will bear this out.. again and again. It's proven. It's using the 'mutts'(other words, the birds can be 'goodness knows what they have genetically..) & not understanding the gene crossover that makes this concept seem confusing.
As sonoran said, it's not strictly 100% as a well known genetic process called 'crossing over' can and DO happen and throw the occasional single combed hen that lays blue/green eggs or peacombed hen laying brown eggs.
It's due to this crossing over plus my own selection that most of my blue/green egg layers are single combed. Just a little quirk that delights me..
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