genetics notes এর চিত্র ফলাফলMultiple allele.
Multiple allele is a situation where by more than two alleles are controlling a certain characteristic. For example alleles A, B and O control the ABO blood group system in man.
Other conditions in Man transmitted in mendellian fashion. (Monohybrid inheritance in man)
  1. 1.       Albinism
Is a condition which results when the pigment for normal skin colour fails to form and this due to a recessive gene a.
Characteristics of albinism
White skin, Pink eyes and Golden hair.
To obtain an albino the child must receive recessive genes from both parents. This implies that an albino is homozygous recessive.
Gene for normal skin pigment: A and gene for Albino: a
Homozygous dominant: (AA) normal skin colour
Heterozygous:                  (Aa) Normal skin colour
Homozygous recessive: (aa) Failure of formation of normal skin pigment (albino)
To get a child who is an albino:
I)        Both parents must be carriers
Parents           Mother (carrier)           X                father (carrier)
Genotype                 A a                                             A a
Gametes
Random fertilization
AA      aa                        Aa                          Aa
AA: normal skin colour
Aa: Normal skin colour but carrier
aa: Albino
II)      One parent is a carrier and the other is an albino
Parents           Mother (albino)           X               father (carrier)
Genotype                 a  a                                            A  a
Gametes
Random fertilization
Aa       aa                    Aa                       aa
Aa: normal skin colour but carrier
aa: albino
From the above two marriages, the mode of transmission of genes is similar to the mendellian fashion.

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