The inheritance of colour in domestic pigeons involves several genes. The dominance hierarchy of three colour alleles is ash-red > blue-black > brown (ZA > ZB > Zb ). These colours are carried on the Z sex chromosome. Unlike humans, female pigeons have two different sex chromosomes (Z and W) and males have two of the same kind of sex chromosome (ZZ). In birds, males have two Z sex chromosomes (ZZ) and females have one Z and one W sex chromosome (ZW). Since female birds have only one Z chromosome, they have only one copy of all Z-linked genes and they express the phenotype of the allele that they get. Barred is a sex-linked dominant trait in chickens. The barring allele causes white pigment in bars on a solid color producing an alternating pattern. The original solid color in the chickens below is black. The possible genotypes and their corresponding phenotypes are as follows: Genotype Gender Feather Phenotype ZBZB Male Barred ZBZb Male Barred ZbZb Male Black ZBW Female Barred ZbW Female Black Which of the following rows correctly displays the phenotypes of the F1 generation of a cross between a pure breeding barred rooster and a black hen AND a black rooster and a barred hen, respectively? Select one: a. Barred Male Black Female Black Male Barred Female Barred males and black females 100% barred b. Barred Male Black Female Black Male Barred Female 100% barred 2 barred females : 1 barred male : 1 black male c. Barred Male Black Female Black Male Barred Female 100% barred 100% barred d. Barred Male Black Female Black Male Barred Female 100% barred Barred males and black females
The inheritance of colour in domestic pigeons involves several genes. The dominance hierarchy of three colour alleles is ash-red > blue-black > brown (ZA > ZB > Zb ).
These colours are carried on the Z sex chromosome. Unlike humans, female pigeons have two different sex chromosomes (Z and W) and males have two of the same kind of sex chromosome (ZZ).
In birds, males have two Z sex chromosomes (ZZ) and females have one Z and one W sex chromosome (ZW). Since female birds have only one Z chromosome, they have only one copy of all Z-linked genes and they express the phenotype of the allele that they get.
Barred is a sex-linked dominant trait in chickens. The barring allele causes white pigment in bars on a solid color producing an alternating pattern. The original solid color in the chickens below is black.
Genotype | Gender | Feather Phenotype |
---|---|---|
ZBZB |
Male | Barred |
ZBZb | Male | Barred |
ZbZb | Male | Black |
ZBW | Female | Barred |
ZbW | Female | Black |
Which of the following rows correctly displays the phenotypes of the F1 generation of a cross between a pure breeding barred rooster and a black hen AND a black rooster and a barred hen, respectively?
Barred Male Black Female | Black Male Barred Female |
---|---|
Barred males and black females | 100% barred |
Barred Male Black Female | Black Male Barred Female |
---|---|
100% barred | 2 barred females : 1 barred male : 1 black male |
Barred Male Black Female | Black Male Barred Female |
---|---|
100% barred | 100% barred |
Barred Male Black Female | Black Male Barred Female |
---|---|
100% barred | Barred males and black females |
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