Quiz 8 Genomes, Development, Phylogeny

A  It can tell us the consistence of proteins in bacteria billion of years ago.

B  It can show how many years (usually in millions) it took for an ancestor to diverge into to different species.

C  It can show how different one language is from another.

A  Introns and exons accumulate mutations at different rates, and also the three positions for a base in a protein-coding codon.

B  Only protein-coding DNA sequences are reliable to use, and since there are so few of them in the genome, DNA analysis is rarely used.

C  DNA analysis can only be used for procaryotes, because they have no introns.

A  When several species are the same and share no differences, it is difficult to sort them into a phylogenetic tree.

B  Wherever hox genes are involved, we can’t use the number of any organs to compare similarities or differences.

C  Similarities don’t always share common ancenstry as they can develop independently.

A  Rule of homoplasy.

B  Method of parsimony.

C  Incomplete lineage sorting.

A  Derived character states only resemble inherited features and were aquired independently, through convergent evolution.

B  Several species may have a common feature (e.g. hair) they inherited from a common ancestor, which had a basic form of that feature.

C  Derived character states are hypothetical models predicting future patterns of evolution.

A  No, because if all individuals of the population have the ability to change in response to the environment, there can be no directional selection.

B  Yes, a feature can become permanent through genetic assimilation.

C  Yes, because a species can change looks and mate with a different species (mimicry-hybridization).

A  It is a prehistoric fly that was created from Dinosaur blood. A million years ago this species had 4 wings.

B  This fly clearly suffers a chromosome duplication, and probably also has twice the numbers of legs and other organs.

C  It suffers a mutation of hox genes regulating the position of structures along head-tail axis, and that gave this fly a second pair of wings.

A  The DNA sequence for bones is present in all cells, and through differential gene regulation it is expressed in the skin (heteropy).

B  The DNA transcription and expression for bones normally occurs earlier in the development, but is delayed and expressed last in these cases, when the skin is formed (heterochrony).

C  Formation of bone-like structures in the skin is due to an SNP (single nucleotide polymorphism) leading to morphological plasticity.

A  Mutations in those regulatory regons of the DNA can either have no effect at all, or lead to neoteny, where the individual retains its juvenile or youth form (dwarfism).

B  Possibly different gene expression, the coding sequence following the operon might be read twice, or wrong (e.g. forward slippage), or not at all.

C  Mutations in any non-coding regions, including promoter or enhancer regions or operons have no effect as they cannot change what amino-acid is transcribed, only how many.

A  Because only 2% of our DNA are exons that are actually transcribed into phenotypic traits.

B  Because we have 2 times more DNA than other organisms.

C  Because the same DNA can be duplicated and achieve twice the differences.