In goats the development of the beard is due to a recessive

In goats, the development of the beard is due to a recessive gene. The following cross, shown below, involving true-breeding goats was made and carried to the F_2 generation. Identify a model of inheritance of the beard development in goats. a recessive lethal allele codominance sex influenced inheritance sex-limited inheritance a dominant lethal allele multiple alleles

Solution

Answer: d. Sex-influenced inheritance

Explanation:

sex-influenced inheritance. Inheritance that is autosomal but has a different intensity of expression in the two sexes, as that manifested in male pattern baldness.

B= Beareded (dominant); b= Bearded

XX; BB vs XY; bb

XX Bb & XY Bb

XB

Xb

YB

Yb

XB

XXBB (bearded)

XXBb (beardless)

XYBB (bearded)

XYBb (bearded)

Xb

XXBb (beardless)

XXbb (beardless)

XYBb (bearded)

XYbb (beardless)

	XB	Xb	YB	Yb
XB	XXBB (bearded)	XXBb (beardless)	XYBB (bearded)	XYBb (bearded)
Xb	XXBb (beardless)	XXbb (beardless)	XYBb (bearded)	XYbb (beardless)