Answer:
D
Explanation:
The presence of homeotic genes shows that all of the listed organisms (mice, flies, humans etc) all evolved from a common ancestor.
(A) is wrong as the evidence of the same gene existing in vastly different species shows the evolutionary relationship between these organisms.
(B) is wrong as there is insufficient evidence to prove that flies are the precessor of humans. We do know that flies and humans have evolved from a common ancestor though.
(C) is non-conclusive as the passage said nothing about the gene allowing the species to have a higher chance of surviving and reproducing. Hence, an errornous claim.
(D) is the correct answer as from a common ancestor, all of the listed organisms undergo and accumulates mutation, undergoes selective pressures that resulted in divergent evolution (aka branching evolution that results in many noval species forming) after millions of years.
Answer:
A frameshift changes every codon past it. A base substitution only changes one codon.
Explanation:
DNA is comprised of nucleotides (A, C, T, G) that make up amino acids. Every three bases is called a codon and represents an amino acid.
In a frameshift mutation, a nucleotide is either added or deleted from the sequence. This offsets the entire sequence after it because the reading frame shifts. Here's an example:
ACTGCTATCGTCATC
If another T is added in between the first and second codons, then every codon after will be changed.
ACT>T<GCTATCGTCATC
A substitution mutation is usually less severe, as it only alters one codon in the sequence. These occur when one nucleotide is replaced by another one. Here's an example:
ACTGCTATCGTCATC
Let's say the first G is replaced by a T.
ACT>T<CTATCGTCATC
As you can see, none of the other codons changed.
Typically, a frameshift mutation is considered worse than a substitution mutation.
Answer:
A homozygous dominant genotype is one in which both alleles are dominant.
Explanation:
For example, in pea plants, height is governed by a single gene with two alleles, in which the tall allele (T) is dominant and the short allele (t) is recessive.
The answer is D) Stationary
(Not a 100% on this but, I'm like 90)
