时间:2019-01-02 作者:英语课 分类:60秒科学


英语课

Mosquitoes, Not Birds, Made West Nile National


In 1999 West Nile virus infected its first American, in New York. By 2004, the disease had spread across the country. Researchers speculated that, for the disease to spread so far so quickly, birds must have helped. Some species could carry the disease and pass it on to mosquitoes, which would then infect humans. But a report published March 2nd in the journal Molecular 1 Ecology [not available online as this episode was posted] says mosquitoes didn’t need a middleman. Or in this case, a middle bird.


Researchers [Jason Rasgon, Bloomberg School of Public Health, Johns Hopkins and Meera Venkatesan, Howard Hughes Medical Institute] noticed that West Nile virus didn't move north-south along migratory 2 bird routes. Nor did it "leap frog" across large areas in the manner of a bird traveling far from where it was infected.


The scientists focused on a different suspect and obtained mosquito DNA 3 from 20 sites in the western U.S. They found three clusters of a species known to carry West Nile.


Surprisingly, they found extensive gene 4 flow between these populations, which meant mosquitoes traveled between groups. In some cases, these mosquitoes covered a range just as large as that of the birds first fingered in the outbreak. So bird lovers take heart, your feathered friends are innocent avians.

 



adj.分子的;克分子的
  • The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
  • For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时,分子的碰撞就停止了。
n.候鸟,迁移
  • Many migratory birds visit this lake annually.许多候鸟每年到这个湖上作短期逗留。
  • This does not negate the idea of migratory aptitude.这并没有否定迁移能力这一概念。
(缩)deoxyribonucleic acid 脱氧核糖核酸
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
n.遗传因子,基因
  • A single gene may have many effects.单一基因可能具有很多种效应。
  • The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。
学英语单词
afoords
aristoloside
audio technology
auditing around the computer
automatic block installation
b. suprapatellaris
Bangued
Bislama
blast amount meter
blepharomelasma
Bukit Timah
car roof
cascaron
charging dynamo
cluster radioactivity
common trust fund
Coningham
Cotoneaster divaricatus
currejong
customer's ledger
desterilizing gold
diagravitropism
diphenhydramines
double work time
Draba jucunda
echo power
electric cooker range
eolian placer
experimental psychopathology
final registration
flat compounding
floating-point radix
formed height of un-loaded single disc
Futures option
gesto
glucosamine-6-phosphate
healthcare facilities
heavy pumping
henrey
high level job control language
idionodal rhythm
in breeding program
inflammable compressed gases
inserted fraise
instrumentalis
iodoxy-
iridium(iv) hydroxide
jaunting cars
jet method
kentel
leafen
locking frequency
marback
monolithic patch
myxofibrcmata
notaire
notch filter
notch grinder
obliger
oil red
olfactic
oral gangrene
orderly market
Oxon.
palladium(ii) palladium(iv) sulfide
patch reef
periodic discharge
phase of folding
phytophily
picture string character
plant mulching
Point Samson
Police Navidad
potassium metamolybdate
preembargo price
raggery
remontant
reticulate duct
rotation perception
runaway star
salmon peel
second brief
set-up-scale meter
shahanshahs
sheared diagram
sinocythere yowdyi
some such
sownder
spacecraft material
spring conjunctivitis
steel heald
suck lemons
table roll
tapping voltage
tartre
tone signal
ungrandiloquent
unrelevant
win eminence
wish sb success
Zenadrex