时间:2019-01-08 作者:英语课 分类:Scientific American(三)月


英语课

This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.


Mark Twain called it "the most delicious fruit known to men." He was talking about the cherimoya. If you never heard of it, there's good reason. It has a feature that has prevented it from becoming widely popular—numerous big seeds fill its sweet white flesh.


But now scientists in Spain and at the University of California, Davis have found the key to making the cherimoya and related fruits seedless. They published their research in the Proceedings 1 of the National Academy of Sciences.


It's generally tough to develop a seedless fruit—bananas and oranges are rare successes. Breeding for seedlessness usually fails to produce the fully 3 developed fruit consumers demand. But the scientists found a spontaneous mutation 4 that causes seedlessness in a cherimoya relative, the sugar apple. They compared its genome to that of a seedless mutant of a plant called Arabidopsis that's used in a lot of research.


In both cases, they found a deletion of one particular gene 2. The researchers say this is the first time a gene for seedlessness has been determined 5. If they can find a way to knock out that gene in the cherimoya, it could bring Mark Twain's favorite fruit, and many others, to a grocery store near you.


Thanks for the minute. For Scientific American's 60-Second Science, I'm Cynthia Graber.



n.进程,过程,议程;诉讼(程序);公报
  • He was released on bail pending committal proceedings. 他交保获释正在候审。
  • to initiate legal proceedings against sb 对某人提起诉讼
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。
adv.完全地,全部地,彻底地;充分地
  • The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气,然后全部呼出。
  • They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。
n.变化,变异,转变
  • People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
  • So far the discussion has centered entirely around mutation in the strict sense.到目前为止,严格来讲,讨论完全集中于围绕突变问题上。
adj.坚定的;有决心的
  • I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
  • He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。
标签: sss 托福素材
学英语单词
advanced feed-hole
anecdotalism
apotracheal banded parenchyma
Arcimboldo, Giuseppe
area air defense commander
as like as not
asymmetry potential
autoalloploid
availability zones
Bacillus leichmannii I
back current step
be computed and taxed separately
biradical initiation
Bleneau
board jump pit
bounding mydriasis
californium (cf)
Chandrasekhar limit
chida
chromosome morphology
clipless mercerizing machine
coercive function
continuous deodorization tower
curing group
cyclosiloxane
deck ankles
dendrocolaptid
diadem spider
Dime Box
direct financing leases
double cyclone
effluxions
El Houbra
ensignment
error logging
Fee-for-service(FFS)
firekeeper
first-aid cabinet
flutazolam
Fort Rupert
frailed
gastrilegous
Greek masonry
heliothis moths
installed positions and shapes
intellectual tourism
Juncus leucanthus
Kedon
kylin
line-sequential color-television
locust beans
long-grain rice
Mambrilla de Castrejón
mcphaden
megalencephalic
Melville I.
methasterone
methylnicotinic acid
misobservance
multilines
multiple-degree-of-freedom system
Nambroca
non specialized
Ovocylin
partial layngec tomy
peripheral nerve paralysis
phase drift
phospholemman
pico-coulombs
Pomona green
precipitin tests
predicative
primary consumer
promoterless
regional centre for technology transfer
Revsnes I.
riemann-hilbert
ringle-straw
satellite injection system
scolecithricella schizosoma
self-conjugate
Sivaists
slackens
social concensus
soleid
spanielled
spin doctoring
sports-drink
srmc
subjective loudness scale
subventionizes
surfacing of roofing material
takes effect
thematical
thermooxidative aging
tidal cycle
towelless
transgenderist
twinspots
under mild restriction
wagon-headed dormer
written record