RESEARCH HIGHLIGHTS

Vol 461|24 September
NATURE|Vol
461|24 September
2009
2009

blood-vessel cells in the diseased mice anddeliver a gene coding for an enzyme that helps
to reverse the effects of the storage defect.

NEUROBIOLOGY

Shocktopus

BIOLOGY LETTERS/THE ROYAL SOCIETY 2009

Curr. Biol. doi: 10.1016/j.cub.2009.07.067 (2009)

Octopuses have the peculiar challenge ofcontrolling eight appendages that can assume
an almost limitless number of positions. They
seem to accomplish this by consolidating thecontrol of complex, coordinated movements
into specific areas of their nervous system —rather than having a one-to-one relationshipbetween a body part and a specific brain area.
Letizia Zullo, now at the Italian Instituteof Technology in Genova, and her colleagues
placed electrodes in 35 parts of the animal’s
nervous system. Low-voltage stimulationof different areas evoked simple responses,
such as a change in skin colour or small
eyelid movements. Higher voltages elicited
more complex responses, such as inking andjet-propelled swimming.
GENE THERAPY

Panning for phage
Nature Medicine doi:10.1038/nm.2025 (2009)

Viruses can be modified to deliver therapeutic
genes directly to the blood vessels feeding
diseased brains, according to research by
Beverly Davidson and her colleagues at theUniversity of Iowa in Iowa City. To identify
address labels for the diseased blood vessels,
the team used the technique of ‘phagepanning’. Millions of particles of a bacterial
virus — phage — displaying different mouseproteins on their surface were injected into theblood of mice with a lysosomal storage disease.
Phages that stuck to diseased-brain bloodvessels were isolated and the protein sequences
responsible for binding were identified.
When these sequences were engineered into
the outer shell of an adeno-associated virus,
AAV2, they enabled AAV2 to target brain

JOURNAL CLUBMikiko C. Siomi
Keio University School ofMedicine, Tokyo, Japan
A biologist praises a mousemodel of autism inheritance.
Autism, a neurodevelopmental
disorder that affects people’s socialabilities, has both genetic andnon-genetic causes. Chromosomal
abnormalities account for
10–20% of autism cases, with
duplication of a long stretch ofchromosome 15 being the mostcommon. I was excited to read

EVOLUTIONARY BIOLOGY

Well endowed
Biol. Lett. doi:10.1098/rsbl.2009.0637 (2009)

The wide variation in male genitalia size inanimals is thought to have evolved mostly
in response to selection
pressures that come into playduring or after copulationand increase the male’s shareof paternity.
But it seems that females ofthe mosquito-fish Gambusia
holbrooki choose mates before
copulation on the basis of thesize of their genitalia — andfor them, bigger is better.
Andrew Kahn and his teamat the Australian National
University in Canberra tested
female preference for males
that had had their genitalia
considerably reduced in sizeby surgery (pictured, bottom) compared withthose with only a minor reduction (pictured,top). They found that females spent, onaverage, around one-and-a-half times longer
associating with the better-endowed males.
ANALYTICAL CHEMISTRY

Evaporating flesh
Angew. Chem. Int. Ed. doi:10.1002/anie.200902546(2009)

Cancer surgeons cutting out tumours in theoperating theatre can find it hard to spot thedifference between malignant and healthy
tissue. But Hungarian scientists say it should
be possible to identify tissue types in real timethat a mouse model with a similar
chromosomal duplication has been
generated (J. Nakatani et al. Cell
137, 1235–1246; 2009). These mice
exhibit the inflexible behaviour,social abnormalities and increased
anxiety often observed in people
with autism. However, whereas
the engineered mice inherit theduplication from their fathers,
human autism cases caused bysuch a duplication are usuallyinherited maternally. Further
genomic analysis in the mice shouldfind the reason for this discrepancy.
This model deserves specialattention as the chromosomal

during surgery, using a mass spectrometerto analyse the ions sprayed up by a standard
surgical electrode as its electric current
evaporates living flesh.
Zoltán Takáts at Semmelweis University,
Budapest, and his colleagues discoveredthat different tissues yield characteristic
sets of gaseous molecular ions as they arebeing dissected — and that the ions canbe pumped to a mass spectrometer andanalysed in less than asecond to distinguish various
grades of cancerous tissue.
AQUATIC TOXICOLOGY

Mixed-up fish
Aquatic Toxicol. doi:10.1016/j.aquatox.2009.08.001 (2009)

Pollutants such as effluent
wastewater, pesticides andpharmaceuticals in rivers
are suspected to cause theintersex condition in fish, inwhich reproductive tissues
are mismatched: mostoften, female germ cells arepresent in the testes.
To assess the incidence of the conditionin river fish throughout the United States,
Jo Ellen Hinck, a US Geological Survey
scientist in Columbia, Missouri, and her teamsampled 111 sites spread across the country.
Intersex fish were found in 31% of the sites,with the greatest prevalence in the south-east.
Small and largemouth bass were the species
most commonly affected.
Correction
The Research Highlight ‘Aluminium arches’(Nature 461, 318; 2009) incorrectly referred to analuminium powder used in the experiment. In fact,
an aluminium oxide powder, alumina, was used.

duplication is stably maintained
between generations. Also, genes
in the duplicated regions seem towork; that is, the expression levelsof genes — including HBII52, which
affects the function of serotonin, amolecule that has cognitive roles inmood, memory and learning — arehigher in the mice, as would be
expected with a gene duplication.
Accumulated evidence showsthat variations in gene-copy
number, such as the chromosomal
duplication in this model, areassociated with susceptibility tovarious human diseases; cancer
cells, for example, tend to have

© 2009 Macmillan Publishers Limited. All rights reservedhigh gene-copy numbers. Thus,
this mammalian model may help us
to understand the molecular basisof autism and to investigate thecontribution of gene duplication inother genetic diseases. This should
encourage many researchers toproduce other model systems
for copy-number variation using
similar techniques; systems that
may clarify the contribution ofchromosomal duplication, or eventhe lack of it, in common diseases
such as diabetes.
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