今日主題:Give Us This Day The Bread Wheat Genome
我們來研究一下麵包小麥的基因組
洪欣老師推薦:托福聽力最好的課外教材:60-Second Science
康康精選托福會考的主題,堅持每天精聽一定會進步的哦!!
建議方法:
1. 先聽兩三遍 (不看文稿)
2. 再一句一句聽寫 (每句都要聽寫數遍,直到寫出85%以上的字)
3. 最後check文稿,看哪聽不出來,單字沒背過,還是發音不熟。
4. 堅持天天聽,就能每天進步哦。
MP3音檔 (按右鍵可下載聽):喜歡的同學,幫忙推或按讚哦~~
http://online1.tingclass.net/voaspe/…/20140718sa_science.mp3
只有音檔怎夠,聽不懂地方,不用怕,康康幫你準備好中英文稿了:
中英文稿:
Wheat helped create civilization in the Middle East. It’s a staple crop for 30 percent of the world’s population. And now, with the publication of four articles in the journal Science, we’re close to a detailed understanding of the bread wheat genome.
小麥幫助中東創造了文明,它是養活了世界30%人口的主要作物。現在,在《科學》雜誌發表的四篇文章的幫助下,我們對於麵包小麥的基因有了一個比較詳細的理解。
Wheat is tough to sequence. It’s gone through multiple hybridizations, making its genome five times larger than a human one. Plus there are many redundancies: more than 80 percent of the genome is made of repeated DNA sequences. So the typical whole-genome shotgun approach—breaking genomes into segments and then reassembling them—doesn’t work for wheat.
小麥的基因組被認為是按順序排列的,它通過複合雜交,使得其基因組比人類的大五倍。再加上這有很多的冗餘,80%多的基因組是由重複的DNA序列組成的。所以典型的全基因體隨機法—把基因組分裂成片段,再將它們進行重組的方法,並不適用於小麥。
Instead, an international consortium devised another strategy, involving physically mapping individual chromosomes and chromosome arms.
然而,一家國際研究中心設計了另一種策略,對單個染色體和染色體臂進行物理映射。
One paper details a draft of the entire genome of bread wheat. Another identifies all the genes on the largest of the plant’s 21 chromosomes. Some 75,000 genes have been mapped. The methods in the second paper will help scientists map the remaining chromosomes. They say it should take another three years.
一篇文章詳細繪製了整個麵包小麥基因租的草圖。另外一個方法可以識別植物最大的21條染色體上的全部基因,大約75000個基因被映射。第二篇文章中的方法可以幫助科學家映射其餘的染色體。他們稱這應該需要3年的時間來完成。
Knowing exactly which genes are responsible for talents such as tolerating drought or improving yields should allow researchers to mine the genome and to quickly produce new and better wheat varieties to bring us our daily bread.
清楚知道什麼基因可以有抗旱和提高產量的特質,就可以讓科學家去開採基因和迅速研製更好的小麥品種,這就會為我們帶來我們每天要吃的麵包。
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