Following statements are regarding to the early development in sea urchin.

A. most cells of the 16-cell embryo, the large micromeres are autonomously specified.

B. large micromeres inherit maternal determinants that were deposited at the vegetal pole of the egg; these become incorporated into the large micromeres at the fourth cleavage.

C. The conditionally specified large micromeres are now able to produce paracrine and juxtacrine factors that autonomously specify the fates of their neighbors.

D. Large micromeres become skeletogenic mesenchyme cells that will leave the blastula epithelium, enter the blastocoel, migrate to particular positions along the blastocoel wall, and then differentiate into the larval skeleton.

Which of the following statement is false?

#Question id: 5217

#Unit 11. Evolution and Behavior

Multigene families include two or more nearly identical genes or genes sharing nearly identical sequences. A classical example is the set of genes for globin molecules, including genes on human chromosomes 11 and 16. How might identical and obviously duplicated gene sequences have gotten from one chromosome to another?

#Question id: 5218

#Unit 11. Evolution and Behavior

Several of the different globin genes are expressed in humans, but at different times in development. What mechanism could allow for this?

#Question id: 5219

#Unit 11. Evolution and Behavior

What is it that can be duplicated in a genome?

#Question id: 5220

#Unit 11. Evolution and Behavior

In comparing the genomes of humans and those of other higher primates, it is seen that humans have a large metacentric pair we call chromosome #2 among our 46 chromosomes, while the other primates of this group have 48 chromosomes and any pair like the human #2 pair is not present; instead the primate groups each have two pairs of midsize acrocentric chromosomes. What is the most likely explanation?

#Question id: 5221

#Unit 11. Evolution and Behavior

Unequal crossing over during Prophase I can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin, known as hemoglobin Lepore, is known in the human population. Hemoglobin Lepore has a deleted set of amino acids. If it was caused by unequal crossing over, what would be an expected consequence?

#Question id: 5222

#Unit 11. Evolution and Behavior

 When does exon shuffling occur?