circumstances with females was the stress of trying to think of things
to talk about. With Candace, he didn’t have time to think. She
maintained a running conversation. During the ascent of the two flights
of stairs she managed to bring up the weather, the town, the hospital,
and how the surgery had gone.
‘This is my lab,’ Kevin said, after opening the door.
‘Fantastic!’ Candace said with sincerity.
Kevin smiled. He could tell she was truly impressed.
‘You go ahead and make your call,’ Candace said. ‘I’ll just look around
if it’s okay.’
‘If you’d like,’ Kevin said.
Although Kevin was concerned about giving Esmeralda so little warning
he’d not be there for lunch, she surprised him with her equanimity. Her
only response was to ask when Kevin wanted dinner.
‘At the usual time,’ Kevin said. Then after a brief hesitation, he
surprised himself by adding: ‘I might have company. Would that be a
problem?’
‘Not at all,’ Esmeralda said. ‘How many persons?’
‘Just one,’ Kevin said. He hung up the phone and wiped his palms
together. They were a little damp.
‘Are we on for lunch?’ Candace called from across the room.
‘Let’s go!’ Kevin said.
‘This is some lab!’ she commented. ‘I never would have expected to find
it here in the heart of tropical Africa. Tell me, what is it that you’re
doing with all this fantastic equipment?’
‘I’m trying to perfect the protocol,’ Kevin said.
‘Can’t you be more specific?’ Candace asked.
‘You really want to know?’ Kevin asked.
‘Yes,’ Candace said. ‘I’m interested.’
‘At this stage I’m dealing with minor histocompatibility antigens. You?
know, proteins that define you as a unique, separate individual.’
‘And what do you do with them?’
‘Well, I locate their genes on the proper chromosome,’ Kevin said. ‘Then
I search for the transponase that’s associated with the genes, if
there’s any, so I can move the genes.’
Candace let out a little laugh. ‘You’ve lost me already,’ she admitted.
‘I haven’t the foggiest notion what a transponase is. In fact, I’m
afraid a lot of this molecular biology is over my head.’
‘It really isn’t,’ Kevin said. ‘The principles aren’t that complicated.
The critical fact few people realize is that some genes can move around
on their chromosome. This happens particularly in B lymphocytes to
increase the diversity of antibodies. Other genes are even more mobile
and can change places with their twins. You do remember that there are
two copies of every gene.’
‘Yup,’ Candace said. ‘Just like there are two copies of each chromosome.
Our cells have twenty-three chromosome pairs.’
‘Exactly,’ Kevin said. ‘When genes exchange places on their chromosome
pairs it’s called homologous transposition. It’s a particularly
important process in the generation of sex cells, both eggs and sperms.
What it does is help increase genetic shuffling, and hence the ability
of species to evolve.’
‘So this homologous transposition plays a role in evolution,’ Candace
said.
‘Absolutely,’ Kevin agreed. ‘Anyway, the gene segments that move are
called transposons, and the enzymes that catalyze their movement are
called transponases.’
‘Okay,’ Candace said. ‘I follow you so far.’
‘Well, right now I’m interested in transposons that contain the genes
for minor histocompatibility antigens,’ Kevin said.
‘I see,’ Candace said, nodding her head. ‘I’m getting the picture.
You’re goal is to move the gene for a minor histocompatibility antigen
from one chromosome to another.’
‘Exactly!’ Kevin said. ‘The trick, of course, is finding and isolating
the transponase. That’s the difficult step. But once I’ve found the
transponase, it’s relatively easy to locate its gene. And once I’ve
located and isolated the gene, I can use standard recombinant DNA
technology to produce it.’
‘Meaning getting bacteria to make it for you,’ Candace said.
‘Bacteria or mammalian tissue culture,’ Kevin said. ‘Whatever works
best.’
‘Phew!’ Candace commented. ‘This brain game is reminding me how hungry I
am. Let’s get some hamburgers before my blood sugar bottoms out.’
Kevin smiled. He liked this woman. He was even starting to relax.
Descending the hospital stairs, Kevin felt a little giddy while
listening and responding to Candace’s entertaining, nonstop questions
and chatter. He couldn’t believe he was going to lunch with such an
attractive, engaging female. It seemed to him that more things had