如何进行白细胞血型的检验？
参考答案：白细胞血型主要是指人类白细胞抗原（HLA.系统。HLA又称组织相容性抗原。HLA是迄今发现的最复杂的人类遗传标记。
HLA的基因位于第6号染色体紧密连锁（不同位点同时遗传）的基因座位上，分别为A、B、C、D、DR、DP、DQ系统。HLA系统具有高度多态性，其表型有几亿种之多，在随机人群中HLA分型完全相同的可能性很小。在亲子鉴定中，HLA不仅可以排除亲子关系，还可以肯定亲子关系。
| "You’re off to the World Economic Forum " asked the Oxford economist, enviously. "How very impressive. They’ve never invited me." Three days later, I queued in the snow outside the conference center in Davos, standing behind mink coals and cashmere overcoats, watched over by Swiss policemen with machineguns. "Reporting press You can’t come in here. Side entrance, please." I stood in line again, this time behind Puffa jackets and Newsweek journalists, waiting to collect my orange badge. Once inside. I found that the seminar I wanted to go to was being held in a half-empty room. "You can’t sit here. All seats are reserved for white badges. Coloured badges have to stand." An acquaintance invited me to a dinner he was hosting: "There are people I’d like you to meet." The green-badged Forum employee stopped me at the door. "This is a participants’ dinner. Orange badges are not allowed." Then, later, reluctantly: "If you’re coming in. please can you turn your badge around Dinners may be upset if they see you’re a colour." "Why does anyone put up with being treated like this " I asked a Financial Times correspondent. "Because we all live in hope of becoming white badges," he said. "Then we’ll know what’s really going on." A leading British businessman was wearing a white badge, but it bore a small logo on the top left-hand corner: GLT. "What’s a GLT " I asked. Ah, he said. "well, it’s a Davos club. I’m a Global Leader for Tomorrow." "That sounds very important," I said. "Yes." He said, "I thought so myself until I bumped into the man who had sponsored me. On the way to my first meeting. I asked him if he was coming, and he said, "Oh no, dear boy, I don’t bother with that any longer. I’m not a GLT any more I’m an IGWEL." "What’s an IGWEL " I asked him. "A member of Informal Group of World Economic Leaders of Today." The World Economic Forum has employed a simple psychological truth — that nothing is more desirable than that which excludes us — to brilliant effect. Year after year, its participants apply to return, in the hope that this time they’ll be a little closer to the real elite. Next year, they, too, might be invited to the private receptions for Bill Clinton, Kofi Annan or Bill Gates instead of having to stand on the conference center’s steps like teenage rock fans. It’s the sheer concentration of individuals in possession of power, wealth or knowledge that makes the privately run Forum so desirable to its participants. The thousand chief executives who attend its annual meeting control, between them, more than 70 percent of international trade. Every year, they are joined by a couple of dozen presidents and prime ministers, by senior journalists, a changing selection of leading thinkers, academics and diplomats, and by rising stars of the business world. Access to the meeting is by invitation only, costs several thousand pounds a time for business participants, and is ruthlessly controlled. |
Which of the following does NOT suggest that the forum is ruthlessly controlled’
A．(A) Participants must hold letters of invitation.
B．(B) Participants should queue in the snow outside.
C．(C) Swiss policemen have to carry machine-guns.
D．(D) Forum employees could check anybody if they wish.