A relatively mild condition caused by the presence of a single gene for sickle cell anemia, producing a smaller amount of abnormal hemoglobin and conferring some resistance to malaria.
- ‘In 1933, L.W. Diggs of Memphis demonstrated the existence of both the asymptomatic sickle-cell trait and the actual disease sickle-cell anemia.’
- ‘To my surprise, I found remarkably high frequencies of sickle-cell trait carriers in tribes living close to the coast of Kenya and near Lake Victoria, whereas in the intervening highlands the frequencies were < 1%.’
- ‘It has also been proposed that the prevalence of sickle-cell trait can influence the genetic structure of parasite populations.’
We take a look at several popular, though confusing, punctuation marks.