# linkage on the sexlinked chromosomes



## Woodnative (Jul 4, 2010)

Can someone tell me, or point me to a resource, of how closely linked the genes on the sex chromosomes are? I am thinking specifically of dilute, the colors (ash red, blue, brown), and the almond family. If I mate a yellow (ash red + dilute) bird with a blue bird.....seems like dilute would be passed on with the ash red........but how much chance do I have of crossing over and ending up with silver (blue + dilute). 

I also have almonds......I think almond is close to the color gene......so if linked with blue (which it is in my case and usually) the chance of crossing over and getting almond linked with ash red is rare (yes, they do exist......but the crossing over rate is low, correct?).

Is almond further from the dilute locus or are they well linked too?


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## indigobob (Nov 12, 2008)

Woodnative,

WF Hollander in his _Origins and Excursions in Pigeon Genetics_ 1983, surmises a crossover rate between the B locus and d locus at about 40% and between the St locus and the B locus a crossover rate of about 3%.
These crossover rates suggest that B locus is not close to the dilute locus but the St locus and the B locus are close to each other.

A dilute almond should be a relatively easy combination to achieve.


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## Woodnative (Jul 4, 2010)

Indigobob Thank you!!! I need to get a copy of that for my own pleasure and reference.


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## jabadao (Jun 11, 2011)

Very interesting.
Indigobob,do you know how many percents for recessive opal spread?
Spread,recessive opal and pattern are on the same chromosome.I try to produce recessive opal spread with an opal cock and a black hen split for opal.....but all squabs are black or recessive opals blue bar.For the moment I never had recessive opal spread or blue bar.


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## indigobob (Nov 12, 2008)

jabadao said:


> Very interesting.
> Indigobob,do you know how many percents for recessive opal spread?
> Spread,recessive opal and pattern are on the same chromosome.I try to produce recessive opal spread with an opal cock and a black hen split for opal.....but all squabs are black or recessive opals blue bar.For the moment I never had recessive opal spread or blue bar.


Jabadao, 
Hollander's book has simple illustrations of the sex chromosome and the autosome with Spread, pattern and recessive opal. He has placed S at one end with C and o at the opposite end, at a similar distance as he places r and d (with a 4% crossover rate). The conclusion would be that he considers them to have a similar crossover percentage.
None of the genetics books I have give a crossover rate - they just say it is a difficult crossover to achieve!


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## jabadao (Jun 11, 2011)

ok,thank you Indigobob.
Patience patience.


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