Free earlobes hang below the point where the ear lobe attaches to the head. Attached earlobes do not hang, but are attached to the head. The gene for free earlobes is dominant (F), while the gene for attached earlobes is recessive (f). Both of Ashley’s parents have free earlobes but also carry a recessive gene for attached earlobes. Ashley has attached earlobes, so she must have
a) one dominant gene for free earlobes.
b) two dominant genes for free earlobes.
c) one recessive gene for attached earlobes.
d) two recessive genes for attached earlobes.
Both of Ashley’s parents have free earlobes but also carry a recessive gene for attached earlobes. Ashley has attached earlobes, so she must have
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Ashley must have d) two recessive genes for attached earlobes.
Since Ashley has attached earlobes, which are determined by the recessive gene (f), she cannot have any dominant genes for free earlobes (F). This means she must have inherited one recessive gene (f) from each parent, resulting in the genotype “ff” for attached earlobes. Both of her parents were carriers of the recessive trait (Ff), which allowed for the possibility of Ashley having attached earlobes.
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