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TLS Online TPP Program

#Question id: 7146

In Drosophila, the neuroectoderm is located ventrally during gastrulation, while in mice or frogs, the neuroectoderm is located dorsally. Which statement best describes how the two systems are similar or different?

#Unit 5. Developmental Biology
  1. There are no similarities between flies and vertebrates in development of the nervous system.
  2. Although gastrulation is completely different in invertebrates and vertebrates, the formation of a neural tube is identical in the two types of animals.
  3. There is little similarity, since the neuroectoderm of invertebrates forms their nervous system with no further morphological changes, while in vertebrates, the neural tube forms a bundle of neurons running along the antero-posterior axis called the spinal cord.
  4. Although the invertebrate nervous system is a ventrally located nerve cord, and the vertebrate spinal cord is located dorsally, homologous genes play a role, and neurons are ultimately specified through a process of lateral inhibition in both cases.
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TLS Online TPP Program

#Question id: 3366

#Unit 11. Evolution and Behavior

Red-Green color blindness is an X-linked recessive disorder. In a population which is in the Hardy-  Weinberg equilibrium, the incidence of occurrence of this in males is 2:2000. What will be the expected incidence of affected homozygous females?
TLS Online TPP Program

#Question id: 3367

#Unit 11. Evolution and Behavior

The largest unit within which gene flow can readily occur is a
TLS Online TPP Program

#Question id: 3368

#Unit 11. Evolution and Behavior

The origin of a new plant species by hybridization, coupled with accidents during nuclear division, is an example of
TLS Online TPP Program

#Question id: 3369

#Unit 11. Evolution and Behavior

Genetic drift refers to random changes in allele frequencies over time leads to following consequence

a. Loss of genetic diversity per generation   

b. change in allelic frequency just by chance 

c. It caused adaptive evolution

d. It one allele may reach to 0 frequency
TLS Online TPP Program

#Question id: 3370

#Unit 11. Evolution and Behavior

One thousand independent populations of Drosophila are established with 25 individuals in each population, of which, one individual is of Aa genotype and the other nine are of AA genotype. If random genetic drift is the only mechanism acting on these populations, then, after a large number of generations, the expected number of populations fixed for the "a" allele is
TLS Online TPP Program

#Question id: 3371

#Unit 11. Evolution and Behavior

If a given gene in a randomly mating population has three alleles a, b and c in the ratio of 0.6, 0.3 and 0.1 respectively, what is the expected frequency of all heterozygote?