Following statements are regarding to convergent extension of the dorsal mesoderm in xenopus.

A. For convergent extension the first force is a polarized cell cohesion wherein the involuted mesodermal cells intercalate and the second force is differential cell cohesion.

B. The intercalations of mesodermal cells, both mediolaterally and radially, are stabilized by the planar cell polarity (PCP) pathway that is initiated by Wnts independent of β-catenin signaling.

C. The intercalations of mesodermal cells, are stabilized by the planar cell polarity (PCP) pathway that is initiated by Wnts dependent of β-catenin signaling.

D. Another factor regulating convergent extension is calcium influx from environment.

E. Ca2+ is released from intracellular stores and is required for convergent extension.

Which of the following combination is correct?

#Question id: 5216

#Unit 11. Evolution and Behavior

Alu elements account for about 10% of the human genome. What does this mean?

#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?