Question

A man with pure blue eyes and pure black hair marries a woman with black eyes and red hair. (Black eyes are dominant over blue eyes and black hair over red hair). What will be the probabilities of phenotypes of the children?
A. 50% with black eyes and black hair, and 50% blue eyes and black hair
B. All will be with black eyes and black hair
C. Both the above cases are possible
D. 1:1:1:1

Answer 1

Hint: Probability is the chance that an event which occurs expressed as a fraction or percentage. There is higher chance of dominant phenotype expression compared to recessive phenotype

Complete answer: Genes are the basic units of inheritance. Genes are passed down the generations. Genes are arranged linearly along the length of chromosome. In a pair of chromosomes one is inherited from mother and the other from father. The pair of genes which control the characteristics are known as allele. Each pair of genes inherited from a particular trait is known as genotype. Phenotype is the physical appearance of the individual which is determined largely by their genes and also by environmental factors. Some genes express more influence known as dominant and the less influence is known as recessive In above question blue eyes is given as allele (bb),black hair (BB) .In female with black eyes (Bb) and red hair (rr). According to the probability concept the dominant trait shows the 75 percent of character and recessive trait shows only 25 percent. The dominant trait in man is black hair is blue eyes .The genotypes which we can get
BbBr , Black eye black hair.
bbBr Blue eye black hair
BbBr Black eye black hair
bbBr Blue eye black hair
so there are 50 percentage chances of black eyes and black hair and 50 percentage chances of blue eyes and black hair
So, the correct answer is “Option A”.

Note: The gene variants code for the same trait (i.e. hair color), but they differ in how the trait is expressed (i.e. black vs blonde hair). The different versions of the same gene are called alleles. Genes can have two or more possible alleles. Individual human have two alleles, or versions, of every gene