Answers
1. a) xx ♀ : xy ♂ (50:50) b) wy ♀ : yy ♂ (50:50) c) wy ♀ : xy ♂ (50:50) d) wx ♀: wy ♂ : xx ♀ : xy ♂ (3♀ : 1♂) e) wx ♀: wy ♀ : xy ♂ : yy ♂ (1♀ : 1♂) f) All males. 2. All males - Sex chromosomes for O. mossambicus female - XX Sex chromosomes for O. hornorum male - ZZ 3. a) All females b) 3 males : 1 female c) All males d) All males e) All males 4. Genotypic ratio - 1 XX : 1 XY ma Phenotypic ratio - 1 grey female ; 1 maculatus male 5. a) Genotypic ratio - 1 Xcp Xcp : 1 Xcp Xcp : 1 XcpY : 1 XchY Phenotypic ratio - 2 caudalis female : 1 caudalis male : 1 transparent tailed male. b) Genotypic ratio - 1 Xcp Xcp : 1 XchY Phenotypic ratio - 1 caudalis♀ : 1 transparent tailed ♂ c) Genotypic ratio - 1 Xch Xch : 1 X cp X ch : 1 X ch Y : 1 X cp Y Phenotypic ratio - 1 transparent tailed ♀ : 1 caudalis ♀ : 1 transparent tailed ♂ : 1 caudalis ♂ 6. XY × XX Black spot ♂ Normal ♀ F 1 XX ♀ : XY ♂ Normal Black spot (50 : 50) Female – homogametic , male – heterogametic If the gene controlling black spot were located on the X – chromosome. XY × XX Normal ♂ Carrier ♀ F 1 XX : XX : XY : XY Carrier ♀ Normal ♀ Normal ♂ Black spot ♂ If the black spot male is crossed with a carrier normal female, XY × XX Black spot ♂ Carrier normal ♀ F 1 1 XY : 1 XX : 1 XY : 1 XX Black spot ♂ Carrier ♀ Black spot ♂ Normal ♀ 7. Wo Zn X Zw Zw Nigra ♀ White ♂ ↓ Wo Zw Zn Zw White ♀ Nigra ♂ ↓ Wo Zn : Wo Zw : Zn Zw : Zw Zw Nigra ♀ White ♀ Nigra ♂ White ♂ Sex determination type is WZ female and ZZ male |