if father is heterozygousRH positive(Dd) and mother is negative(dd) write the possibilities of HDNBto the 1st child,2nd child,and 3rd child
Answers
Answer:A parent with A blood group can have two possible genotypes: “IA IA” and “IA IO”; similarly parent with B blood group can have two possible genotypes: “IB IB” and “IB IO”. If both the parents are homozygous (IA IA x IB IB) , all of their children will have AB blood group. But if father is heterozygous (IA IO”) and mother is homozygous (IB IB); the total different types of possible combinations by three alleles (IA, IB and IO) will be (IA IB and IBIO). But if mother is heterozygous (IB IO) and father is homozygous (IA IA); the total different types of possible combinations by three alleles (IA, IB and IO) will be (IA IB and IBIO).
Cross 1
Parent generation : IA IA x (IB IB)
Gametes :
IA IA-->
(IA IB)
IA IA
IB IAIB IAIB
IB IAIB IAIB
F1 generation phenotypic ratio = All AB group
Cross 2
Parent generation: IA IO X (IB IB)
Gametes
IA IO -->
IB IB
IA IO
IB IA IB IB IO
IB IA IB IB IO
F1 generation phenotypic ratio = 1 AB group : 1 B group
Cross 3
Parent generation: IA IA X (IB IO)
Gametes
IA IA -->
IB IB
IA IA
IB IA IB IA IB
IO IA IO IA IO
F1 generation phenotypic ratio = 1 AB group : 1 A group
Cross 4
Parent generation: IA IO X (IB IO)
Gametes :
IA IO -->
IB IO
IA IO
IB IA IB IB IO
IO IA IO IO IO
F1 generation phenotypic ratio = 1 AB group : 1 B group : 1 A group : 1 O group
Thus, the correct answer is option D.
Explanation:only a explame