Short Answer TypeExplain sex determination in bees.
In honeybees (or honey bees), sex is normally determined by the fertilization or non-fertilization of eggs, rather than the presence or absence of sex chromosomes. This mode of sex determination was first discovered by Johann Dzierzon, a Catholic priest, in 1845. Dzierzon reported that a virgin queen which has not taken a mating flight (the queens mate only while in free flight away from nest) produces only male progeny. His report was the first rigorous description of a sex determination system, occurring more than 50 years before the discovery of sex chromosomes. We now know that honey bees are not unique and that about 20% of animal species use a haplodiploid mode of reproduction. In haplodiploid systems, male progeny normally develops from unfertilized eggs, which are haploid and have just one set of chromosomes. The fertilized honey bee eggs, which are diploid and have two sets of chromosomes, differentiate into queens and worker bees.
Name the type of cross that would help to find the genotype of a pea plant bearing violet flowers.
Both Haemophilia and Thalassemia are blood related disorders in humans. Write their causes and the difference between the two. Name the category of genetic disorder they both come under.
(a) Write the desirable characters a farmer looks for in his sugarcane crop. (b) How did plant breeding techniques help north Indian farmers to develop cane with desired characters ?
Explain the mechanism of ‘sex determination’ in birds. How does it differ from that of human beings?
a) Write the scientific name of the organism Thomas Hunt Morgan and his colleagues worked with for their experiments. Explain the correlation between linkage and recombination with respect to genes as studied by them.
b) How did Sturtevant explain gene mapping while working with Morgan?
Multiple Choice QuestionsAssertion: A middle aged woman is reported to have small breasts and undersized uterus.
Reason: Her genotypic analysis shows XO condition of allosomes.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false
A tall true breeding garden pea plant is crossed with a dwarf true breeding garden pea plant. When the F1 plants were selfed the resulting genotypes were in ratio of
1:2:1 :: Tall heterozygous: Tall homozygous: Dwarf
3:1:: Tall: Dwarf
3:1:: Dwarf: Tall
3:1:: Dwarf: Tall
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