The woman lurched forward and pulled me by my arm. I squealed and twisted out of her grasp and ran behind my father for protection. I wrapped my arms around his waist and held on tightly.

"Show us," demanded the woman. "Prove she is clean enough to travel with this camp."

Da refused, which made the woman lose her temper. She slapped him so hard she split his lip. He tasted the blood, but stood resolute. She reached around and tried to unlock my arms from Da's waist.

He pushed her away.

"She is not fit to share our camp. She should be cut, or else she will be shamed in the sight of Allah,"

the woman screamed. The other women were shouting and shaking their fists, but few of them knew English, so it was as much in confusion as anger.

My father fixed the woman with a vicious glare. "You call my daughter shameful in the sight of Allah?

I am a servant of Allah. Prove to me that Allah is shamed and I will do what I can to remove the shame.

Fetch a mullah."

The woman scowled. "I will fetch a mullah, although I doubt your promise is worth as much as words in the sand."

"Make sure the mullah speaks English," my father demanded as she slipped away. He turned to me and wiped away tears. "Don't worry, Zada. No harm will come to you."

"Will I be allowed to play with Ala?"

"No. Not with these old vultures hanging around."

By the evening, the women had found a mullah gullible enough to mediate the dispute. They tugged his sleeves as he walked toward our camp, hurrying him up. It was obvious that his distaste had grown with every minute in the company of the women, and now he was genuinely reluctant to speak on the matter.

The weathered woman pointed us out to the mullah and spat some words at him that we did not understand.

"Sir, I hear that your daughter is uncirc.u.mcised. Is this true?"

"It is none of your business," said Da.

The mullah's face dropped. You could almost see his heart sinking. "Did you not promise...?"

"I promised to discuss theology with you and that crone. My daughter's anatomy is not your affair."

"Please, sir..."

Da cut him off abruptly. "Mullah, in your considered opinion, is it necessary for a Muslim girl to be circ.u.mcised?"

"It is the accepted practice," said the mullah.

"I do not care about the accepted practice. I ask what Mohammed says.""Well, I'm sure that Mohammed says something on the matter," said the mullah.

"Show me where."

The mullah coughed, thinking of the fastest way to extract himself. "I did not bring my books with me," he said.

Da laughed, not believing that a mullah would travel so far to mediate a theological dispute without a book. "Here, have mine," Da said as he pa.s.sed the Qur'an to the mullah. "Show me where Mohammed says such a thing."

The mullah's shoulders slumped. "You know I cannot. It is not in the Qur'an. But it is sunnah."

"Sunnah," said Da, "is very clear on the matter. Circ.u.mcision is makrumah for women. It is honorable but not compulsory. There is no requirement for women to be circ.u.mcised."

"Sir, you are very learned. But there is more to Islam than a strict reading of the Qur'an and sunnah.

There have even been occasions when the word of Mohammed has been overturned by later imams.

Mohammed himself knew that he was not an expert on all things, and he said that it was the responsibility of future generations to rise above his imperfect knowledge."

"So, you are saying that even if it was recorded in the Qur'an, that would not make it compulsory."

Da gave a smile, the little quirk of his lips that he gave every time he had laid a logical trap for someone.

The mullah looked grim. The trap had snapped shut on his leg, and he was not looking forward to extricating himself.

"Tell these women so we can go back to our tents and sleep," said Da.

The mullah turned to the women and spoke to them. The weathered woman became agitated and started waving her hands wildly. Her voice was an overwrought screech. The mullah turned back to us.

"She refuses to share camp with you, and insists you leave."

Da fixed the mullah with his iron gaze. "Mullah, you are a learned man in a difficult situation, but surely you can see the woman is half-mad. She complains that my daughter has not been mutilated, and would not taint herself with my daughter's presence. Yet she is tainted herself. Did she tell you that she tried to a.s.sault my daughter and strip her naked in public view? Did she tell you that she inflicted this wound on me when I stood between her and my daughter? Did she tell you that I have taken the bloodwriting, so she spilled the Word of G.o.d when she drew blood?"

The mullah looked appalled. He went back to the woman, who started screeching all over again. He cut her off and began berating her. She stopped talking, stunned that the mullah had turned on her. He kept berating her until she showed a sign of humility. When she bowed her head, the mullah stopped his tirade, but as soon as the words stopped she sent a dagger-glance our way.

That night, three families pulled out of our camp. Many of the others in camp were pleased to see them go. I heard one of the grandmothers mutter "Taliban" under her breath, making a curse of the words.

The mood in camp lifted, except for mine. "It's my fault Ala left," I said.

"No, it is not your fault," said Da. "It was her family's fault. They want the whole world to think the way they think and to do what they do. This is against the teaching of the Qur'an, which says that there shall be no coercion in the matter of faith. I can find the sura if you like."

"Am I unclean?"

"No," said Da. "You are the most beautiful girl in the world."

By morning, the camp had been filled by other families. The faces were more friendly, but Ala was gone. It was my first lesson in intolerance, and it came from my own faith.

In Sydney, we sat for hours, waiting to be processed. By the third hour, Da finally lost patience and approached the customs officer.

"We are Australian citizens, you know?" Da said.

"Please be seated. We are still waiting for cross-checks."

"I was born in Brisbane, for crying out loud! Zada was born in Melbourne. My family is Australian four generations back."

His protests made no difference. Ever since the Saladin Outbreak, customs checked all Muslimsthoroughly. Fifty residents of Darwin had died from an outbreak of a biological weapon that the Saladins had released. Only a handful of Saladins had survived, and they were all in prison, and it had been years ago, but Australia still treated its Muslims as if every single one of us was a terrorist waiting for the opportunity to go berserk.

We were insulted, shouted at, and spat on by men and women who then stepped into their exclusive clubs and talked about how uncivilized we were. Once it had been the Aborigines, then it had been the Italian and Greek immigrants; a generation later it was the Asians; now it was our turn. Da thought that we could leave for a while, go on our pilgrimage and return to a more settled nation, but our treatment by the customs officers indicated that little had changed in the year we were away.

They forced Da to strip for a search, and nearly did the same for me, until Da threatened them with child molestation charges. They took blood samples from both of us. They went through our luggage ruthlessly. They X-rayed our suitcases from so many angles that Da joked they would glow in the dark.

Then they made us wait, which was the worst punishment of all.

Da leaned over to me and whispered, "They are worried about my blood. They think that maybe I am carrying a deadly virus like a Saladin. And who knows? Maybe the Qur'an is a deadly virus." He chuckled.

"Can they read your blood?" I asked.

"Yes, but they can't make sense of it without the code sheet."

"If they knew it was just the Qur'an texts, would they let us go?"

"Probably," said Da.

"Why don't you give it to them, then?"

He sighed. "Zada, it is hard to understand, but many people hate us for no reason other than our faith. I have never killed or hurt or stolen from anyone in my life, and yet people hate me because I pray in a church with a crescent instead of a cross."

"But I want to get out of here," I pleaded.

"Listen to me, daughter. I could show them the crib sheet and explain it to them, but then they would know the code, and that is a terrifying possibility. There are people who have tried to design illnesses that attack only Jews or only blacks, but so far they have failed. The reason why they have failed is that there is no serological marker for black or Jewish blood. Now we stupid Muslims, and I count myself among the fools, have identified ourselves. In my blood is a code that says that I am a Muslim, not just by birth, but by active faith. I have marked myself. I might as well walk into a neo-n.a.z.i rally wearing a Star of David.

"Maybe I am just a pessimist," he continued. "Maybe no one will ever design an anti-Muslim virus, but it is now technically possible. The longer it takes the dhimmis to find out how, the better."

I looked up at my father. He had called himself a fool. "Da, I thought you were smart!"

"Most of the time, darling. But sometimes faith means you have to do the dumb thing."

"I don't want to be dumb," I said.

Da laughed. "You know you can choose whatever you want to be. But there is a small hope I have for you. To do it you would need to be very, very smart."

"What?" I asked.

"I want you to grow up to be smart enough to figure out how to stop the illnesses I'm talking about.

Mark my words, racial plagues will come one day, unless someone can stop them."

"Do you think I could?"

Da looked at me with utter conviction. "I have never doubted it."

Da's leukemia recurred a few years later. The chemotherapy had failed to cure him after all, although it had given him seven good years, just long enough to see me to adulthood, and enrolled in genetics. I tried to figure out a way to cure Da, but I was only a freshman. I understood less than half the words in my textbooks. The best I could do was hold his hand as he slowly died.

It was then that I finally understood what he meant when he said that sometimes it was important not to be smart. At the climax of our haj we had gone around the Kaabah seven times, moving in a humanwhirlpool. It made no sense at all intellectually. Going around and around a white temple in a throng of strangers was about as pointless a thing as you could possibly do, and yet I still remember the event as one of the most moving in my life. For a brief moment I felt a part of a greater community, not just of Muslims, but of the Universe. With that last ritual, Da and I became haji and hajjah, and it felt wonderful.

But I could not put aside my thoughts the way Da could. I had to be smart. Da had asked me to be smart. And when he died, after four months and two failed chemo cycles, I no longer believed in Allah. I wanted to maintain my faith, as much for my father as for me, but my heart was empty.

The event that finally tipped me, although I did not even realize it until much later, was seeing his blood in a sample tube. The oncology nurse had drawn 8 mls from his central line, then rolled the sample tube end over end to mix the blood with the anticoagulant. I saw the blood darken in the tube as it deoxygenated, and I thought about the blood cells in there. The white cells contained the suras of the Qur'an, but they also carried the broken code that turned them into cancer cells.

Da had once overcome leukemia years before. The doctors told me it was very rare to have a relapse after seven years. And this relapse seemed to be more aggressive than the first one. The tests, they told me, indicated this was a new mutation.

Mutation: a change in genetic code. Mutagen: an agent that promotes mutation.

Bloodwriting, by definition, was mutagenic. Da had injected one hundred and fourteen suras into his own DNA. The designer had been very careful to make sure that the bloodwriting virus inserted itself somewhere safe so it would not disrupt a tumor suppressor gene or switch on an oncogene-but that was for normal people. Da's DNA was already damaged by leukemia and chemotherapy. The virus had written a new code over the top, and I believe the new code switched his leukemia back on.

The Qur'an had spoken to his blood, and said: "He it is Who created you from dust, then from a small lifegerm, then from a clot, then He brings you forth as a child, then that you may attain your maturity, then that you may be old-and of you there are some who are caused to die before-and that you may reach an appointed term, and that you may understand./He it is who gives life and brings death, so when He decrees an affair, He only says to it: Be, and it is."

I never forgave Allah for saying "Be!" to my father's leukemia.

An educated, intelligent biologist, Da must have suspected that the Qur'an had killed him. Still, he never missed a prayer until the day he died. My own faith was not so strong. It shattered like fine china on concrete. Disbelief is the only possible revenge for omnipotence.

An infidel I was by then, but I had made a promise to my father, and for my postdoc I solved the bloodwriting problem. He would have been proud.

I abandoned the crib sheet. In my scheme the codons were a.s.signed randomly to letters. Rather than preordaining TAT to mean zen in Arabic or "k" in English, I designed a process that shuffled the letters into a new configuration every time. Because there are 64 codons, with three {stop} marks and eight blanks, that comes to about 5 x 1083 or 500,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,0.

00,000,000,000,000,000 combinations. No one could design a virus specific to the Qur'an suras anymore. The dhimmi b.a.s.t.a.r.ds would need to design a different virus for every Muslim on the face of the Earth. The faith of my father was safe to bloodwrite.

In my own blood I have written the things important to me. There is a picture of my family, a picture of my wedding, and a picture of my parents from when they were both alive. Pictures can be encoded just as easily as text.

There is some text: Crick and Watson's original paper describing the double-helix of DNA, and Martin Luther King's "I Have a Dream" speech. I also transcribed Casius's words from Julius Caesar.

The fault, dear Brutus, is not in our stars, But in ourselves, that we are underlings.For the memory of my father, I included a Muslim parable, a sunnah story about Mohammed: One day, a group of farmers asked Mohammed for guidance on improving their crop. Mohammed told the farmers not to pollinate their date trees. The farmers recognized Mohammed as a wise man, and did as he said. That year, however, none of the trees bore any dates. The farmers were angry, and they returned to Mohammed demanding an explanation. Mohammed heard their complaints, then pointed out that he was a religious man, not a farmer, and his wisdom could not be expected to encompa.s.s the sum of human learning. He said, "You know your worldly business better."

It is my favorite parable from Islam, and is as important in its way as Jesus' Sermon on the Mount.

At the end of my insert, I included a quote from the dhimmi Albert Einstein, recorded the year after the atomic bombing of j.a.pan.

He said, "The release of atom power has changed everything but our way of thinking," then added, "the solution of this problem lies in the heart of humankind."

I have paraphrased that last sentence into the essence of my new faith. No G.o.d was ever so succinct.

My artificial intron reads:

CTA AGC GAC GAA TGT AGT CAT TAC GGA AGC TAA CAT CAG TGT TAC TAA GAA.

AGT TGT TAA CAG TGT AGC GAC GAA TGT GAC GAA AAA AGG AGC TGT CAT GAG.

TGT GAC GGA CAA AAA CAG TAT TAA CAG AAC TGC.