In Comparing the Genomes of Humans and Those of Other

question 24

Multiple Choice

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?

• A)The ancestral organism had 48 chromosomes and at some point a centric fusion event occurred and provided some selective advantage.
• B)The ancestral organism had 46 chromosomes, but primates evolved when one of the pairs broke in half.
• C)At some point in evolution, human ancestors and primate ancestors were able to mate and produce fertile offspring, making a new species.
• D)Chromosome breakage results in additional centromeres being made in order for meiosis to proceed successfully.
• E)Transposable elements transferred significantly large segments of the chromosomes to new locations.

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Definitions:

Second Messenger

Intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules.

Ion Channel-linked Receptor

A type of cell surface receptor that opens or closes a channel across the cell membrane in response to the binding of a signaling molecule, allowing specific ions to pass through.

G Protein-linked Receptor

A type of cell surface receptor that activates G proteins in response to the binding of a signaling molecule, playing a pivotal role in various signal transduction pathways.

GDP

Gross Domestic Product, a measure of the economic performance of a country, representing the total value of all goods and services produced over a specific time period.