Short Answer Type(a) Why is human ABO blood group gene considered a good example of multiple alleles?
(b) Work out a cross up to F1 generation only, between a mother with blood group A (Homozygous) and the father with blood group B (Homozygous). Explain the pattern of inheritance exhibited.
Long Answer TypeA child by the family from Thalassemia is born to a normal couple. But the mother is being blamed by the family for delivering a sick baby. (a) What is Thalassemia?
(b) How would you counsel the family not to blame the mother for delivering a child suffering from this disease? Explain.
(c) List the values your counseling can propagate in the families.(a) Thalassemia - is an autosomal recessive blood disease which can occur due to deletion of the genes controlling the formation of globin chains (commonly Alpha and Beta) of haemoglobin.
(b) Mother cannot be blamed for the disease as, it is an autosomal recessive blood disorder. The genes for the synthesis of globin chains are present on autosomes.
(i) Formation of Alpha chain is controlled by 2 genes present on chromosome 16 and
(ii) Formation of Beta-chain is controlled by one gene present on chromosome 11manifestation of the disease occurs when the progeny receives defective genes from both the parents (as thalassemia is expressed is homozygous recessive condition only).
(c) Values that can be propagated in families are
(i) One should be aware of such autosomal diseases and should get themselves checked for the same before marriage.
(ii) Manifestation of the disease occurs due to defective genetic set up of both the parent (so it is not only that the mother should be blamed.Short Answer TypeA garden pea plant (A) produced inflated yellow pod, and another plant (B) of the same species produced constricted green pods. Identify the dominant traits.
Long Answer TypeWhat is the inheritance pattern observed in the size of starch grains and seed shape of Pisum sativum? Workout the monohybrid cross showing the above traits. How does this pattern of inheritance deviate from that of Mendelian law of dominance?
Short Answer Type(a) Sickle celled anaemia in humans is a result of point mutation. Explain.
(b) Write the genotypes of both the parents who have produced a sickle celled anaemic offspring.
How many chromosomes do drones of honeybee possess? Name the type of cell division involved in the production of sperms by them.
During a monohybrid cross involving a tall pea plant with a dwarf pea plant, the offspring populations were tall and dwarf in equal ratio. Work out a cross to show how is it possible.
Long Answer Type(a) Why are thalassemia and haemophilia categorized as Mendelian disorders ? Write the symptoms of these diseases. Explain their pattern of inheritance in humans.
(b) Write the genotypes of the normal parents producing a haemophilic son.
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