Heterogametic Female

Correct Answer: Poultry

From the notes (Table 6 and sex chromosome data): In Poultry (birds), the female is heterogametic (ZW) — produces two types of gametes (Z-bearing and W-bearing eggs).

Sex Determination — Two Systems

• Mammals (cattle, pig, buffalo, human): Male = XY (heterogametic); Female = XX (homogametic)
• Birds (poultry, duck, turkey): Male = ZZ (homogametic); Female = ZW (heterogametic) ✔

Chromosome Numbers (from Table 1 in notes)

• Chicken (Dog): 2N = 78 (76 autosomes + ZZ or ZW)
• Duck: 2N = 80
• Turkey: 2N = 82

Practical Significance

Because the female bird is heterogametic, sex-linked traits in poultry are passed from father to daughter and mother to son — the classic criss-cross pattern. This is used in autosexing — sexing day-old chicks based on plumage colour or feather growth rate.