are sluggish and therefore prone to predation

are restricted to very cold water

have bluish blood

are very small in size

1.9°C

0°C

–1.9°C

–4.9°C

2

about 16

about 50

about 100

1

2

4

8

Vertebrates have multiple copies of the genes that code for globins

The genes that code for globin diverged only recently

In birds and mammals, genes that code for α-globin are located on a different chromosome from those that code for β-globin

In fish, genes that code for globins are found on a single chromosome

homologous sequences

a matching of intron sequences

gene function

the beginning sequence on the chromosome

Redundant gene sequences have been selected against and removed over time

The α-globin gene is nonfunctional; the β-globin gene has been moved to another chromosome but is functional

The α-globin gene is nonfunctional; the β-globin gene has been moved to another chromosome and is nonfunctional

Deletions have rendered the α-globin gene nonfunctional and the β-globin gene has been removed

It shows when icefish diverged from red-blooded fish

It shows the phylogeny of teleost fish outgroups and their relatedness to icefish

It shows an evolutionary tree of 22 species of related Antarctic fish

It shows the relatedness of Antarctic fish that use antifreeze proteins

bone morphology

similarities of mitochondrial DNA

sequences of the hemoglobin genes

sequences of antifreeze genes

I

II

III

Both I and II

All of the species beyond point B share the same missing portions of DNA.

Species beyond points A and B share the same missing portions of DNA

Only species beyond point C share the missing sequences that render hemoglobin nonfunctional

Species beyond points C and D have nonfunctional hemoglobin but the missing sequences are different

I

II

III

Before point I and II

Presence of antifreeze proteins → presence of hemoglobin → loss of functional hemoglobin → loss of functional myoglobin

Presence of antifreeze proteins → presence of hemoglobin → loss of functional myoglobin → loss of functional hemoglobin

No functional hemoglobin → presence of antifreeze proteins → loss of functional myoglobin → presence of functional hemoglobin

Presence of hemoglobin → presence of antifreeze proteins → loss of functional hemoglobin → loss of functional myoglobin

It shows when icefish diverged from red-blooded fish.

It shows the lineages of icefish that have lost functional myoglobin

It shows the lineages of icefish that have regained functional hemoglobin

It shows the lineages of Antarctic fish that use antifreeze proteins

bone morphology

similarities of mitochondrial DNA

sequences of the hemoglobin genes

sequences of antifreeze genes

The sequence changes occurring at the four independent points are very different from one another

The sequence changes occurring at the four independent points are exactly the same

The loss of function resulting from the sequence changes is exactly the same

The morphology of the species at the four independent points is exactly the same

All icefish have nonfunctional myoglobin

Mutations that eliminated myoglobin function occurred independently in four lines of icefish

Mutations that eliminated myoglobin function occurred once in early icefish evolution and have affected six species in different lineages

Identical mutations that eliminated myoglobin function occurred in four separate lineages of icefish

An increase in fitness was shown following the appearance of nonfunctional hemoglobin

The appearance of nonfunctional hemoglobin was accompanied by a decrease in fitness

Icefish have enlarged hearts and faster blood circulation compared to red-blooded fish

Icefish have a very small body size to compensate for the loss of functional hemoglobin

Ventricular myoglobin

Antifreeze glycoproteins

Hemoglobin

Myoglobin

The genes responsible for producing the suite of glycoproteins in Antarctic fish evolved after the appearance of icefish

Glycoproteins reduce the freezing point of blood plasma

Genes coding for glycoproteins are similar in all species of Antarctic fish

When hemoglobin became deleted in icefish, they already had the genes coding for glycoproteins

genome

sequence

transcriptome

proteome

via manual transcription by a team of genetic scientists

using experimental processes

by computers using high-throughput methods

by hand with a team of information scientists

high-throughput processing

information processing

annotation

bioinformatics

Elucidating the evolution of genomes

Elucidating the current function of genes

Elucidating the current function of genomes

Elucidating the evolution of species through genomes

genes coding for plasma albumin

genes coding for pancreatic proteins such as trypsin

spontaneous mutations in intron sequences

insertion events from ancient bacteria

distinctive DNA sequences

distinctive RNA sequences

distinctive gene expression patterns

identical exon sequences

there are no gap junctions in sea urchins

there is no cellular communication system in sea urchins

sea urchins are not related to vertebrates

the cellular communication system of sea urchins is unusual

are not susceptible to diseases

have a long lifespan

are bombarded by pathogens and must react constantly

have unusually elaborate immune and detoxification systems

No genes are present that code for gap-junction proteins

No genes are present that code for the enzymatic synthesis of adrenaline

Genes that code for cytochrome P450 detoxification enzymes are extraordinarily numerous

Genes that code for skeleton mineralization are very similar to those found in vertebrates

The function predicted by extrapolation from already known genes always matches the current function

Even if the function is known, the expression pattern may differ

The function predicted by extrapolation may vary extensively within individuals of the species

Often, the introns within species vary too much between individuals

it is said to enter the postgenomic era

bioinformatics takes over

annotation is all that can take place

functional genomics is all that is left for that species

Animal function → tissue-specific proteins → tissue function → genes

Genes → tissue function → tissue-specific proteins → animal function

Animal function → tissue function → tissue-specific proteins → genes

Genes → tissue-specific proteins → tissue function → animal function

It is specific in searching for proteins and metabolites instead of genes.

It can proceed without preexisting biases regarding which genes are involved in a particular function.

It can focus on a defined phenomenon of known importance to the whole organism.

It is specific in searching for gene expression instead of profiling proteins or metabolites

a survey of substances at II.

the sequencing of I.

an a priori hypothesis regarding III.

an a priori hypothesis regarding IV

II and I.

II and III.

I and III.

I and II.

screening

sequencing

transcriptomics

expression profiling

are all statistically significant, given the number of tests involved

typically are not formed ba priori

produce false positives most of the time

cannot be validated statistically

mRNA

genes

DNA

tRNA

genomics

transcriptomics

proteomics

metabolomics

These genes are not as important as the other two categories in response to exercise

These mRNAs cannot be detected as easily as those of the other two categories

There are fewer genes producing this set of mRNAs compared to those producing the other two categories

Although the mRNAs are produced in small quantities, their half-lives are long

It represents the output of a genomic analysis

It shows a two-species genomic analysis

It is a proteomic output

It is the output of a microarray

hybridize with

bind to

transcribe

reverse transcribe

RNA interference

forced overexpression

gene knockout

expression profiling

proteins.

metabolites.

mRNA.

DNA.

proteins.the response of a selection of mRNAs to malarial parasites

the daily patterns of enzymes that are responsible for combating the malarial parasite

the daily patterns of mRNAs that code for detoxification enzymes

three enzymatic responses to a daily light cycle in the malarial parasite

It shows a two-species genomic analysis

It shows a two-species environmental response at the protein level

It shows the separation of proteins by a gel

It is the output of a microarray

genes.

mRNA.

DNA.

proteins.

It represents the output of an NMR spectrum

It shows a two-species environmental response at the protein level

It shows the separation of proteins by a gel

It is the output of a microarray

The amplitudes of the peaks are used to sequence the metabolite.

The amplitudes of the peaks are irrelevant and only provide information on the presence or absence of metabolites

The amplitudes of the peaks are used to calculate metabolite concentrations.

The order of the metabolites on the spectrum is related to their concentration.