A Plant-Like Organism on the Planet Pandora Can Have Three

question 18

Multiple Choice

A plant-like organism on the planet Pandora can have three recessive genetic traits: bluish leaves, due to an allele (a) of gene A; a feathered stem, due to an allele (b) of gene B; and hollow roots due to an allele (c) of gene C. The three genes are linked and recombine.
A geneticist performed a testcross with an organism that had been found to be heterozygous for the three recessive traits, and she was able to identify progeny of the following phenotypic distribution (+ = wild type) :
$$\begin{array} { | l | l | l | l | l | } \hline \text { Phenotypes } & \text { Leaves } & \text { Stems } & \text { Roots } & \text { Number } \\\hline 1 & a & + & + & 14 \\\hline 2 & a & + & c & 0 \\\hline 3 & a &b &+ & 32 \\\hline 4 & a &b& c & 440 \\\hline 5 & + &b& + & 0 \\\hline 6 & + &b& c & 16 \\\hline 7 & + & + & c & 28 \\\hline 8 & + & + & + & 470 \\\hline & & & \text { Total } & 1000 \\\hline\end{array}$$
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The greatest distance among the three genes is between a and c. What does this mean?

• A) Gene c is between a and b.
• B) Genes are in the order: a-b-c.
• C) Gene a is not recombining with c.
• D) Gene a is between b and c.

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Definitions:

Current Understanding

Refers to the present level of knowledge and comprehension surrounding a particular subject or topic.

Back To Sleep Position

A recommended sleeping position for babies, lying on their back, to reduce the risk of Sudden Infant Death Syndrome (SIDS).

Walking

The act of locomotion on foot, involving a series of rhythmical steps that move the body forward while maintaining stability.

Crawling

A form of movement involving the use of hands and knees, typically seen as an early developmental milestone in infants.