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The Question of Bimodality of Sperm
The Question of Bimodality of Sperm Editor's Note
IN
SEVERAL REPORTS,l-4 one of which was published in the January-February, 1961, number of this Journal under the title "Differences in Human Spermatozoa," Dr. Landrum Shettles described two populations of human spermatozoa observed by him in unstained, dried smears viewed through the dry objectives of a phase-contrast optical system. He found them to be distinguished by differences in the size and shape of nuclei and heads, diffraction of light from the heads, diffraction of light by the discrete chromosomes, the chromosomal arrangements, and the size and shape of the most centrally located chromosome. He concluded that the smallerheaded spermatozoa contain the Y and the larger the X chromosome. These reports created a storm of rebuttal from biologists, zoologists, and microscopists around the world. Since these studies of Dr. Shettles' remain highly controversial, we felt that the Journal could serve a useful scientific purpose in attempting to crystallize the matter. Accordingly, we are publishing in the following pages the latest paper of Dr. Shettles, followed by a critique of his methods and findings by Dr. van Duijn, a biologist and microscopist of distinction. Dr. Shettles has had the opportunity of reading Dr. van Duijn's criticisms and his reply is included. THE EDITOR
REFERENCES 1.
SHETTLES,
L. B.
Nuclear morphology of human spermatozoa.
Nature 186:648,
1960. L. B. X and Y spermatozoa. Nature 187:524, 1960. L. B. Nuclear morphology of human spermatozoa. Obst. & Gynec. 16:10, 1960. 4. SHETTLES, L. B. Nuclear morphology of human spermatozoa. Med. Circle Bull. 7:8, 1960.
2. 3.
SHETTLES, SHETTLES,
501
IN
SEVERAL REPORTS,l-4 one of which was published in the January-February, 1961, number of this Journal under the title "Differences in Human Spermatozoa," Dr. Landrum Shettles described two populations of human spermatozoa observed by him in unstained, dried smears viewed through the dry objectives of a phase-contrast optical system. He found them to be distinguished by differences in the size and shape of nuclei and heads, diffraction of light from the heads, diffraction of light by the discrete chromosomes, the chromosomal arrangements, and the size and shape of the most centrally located chromosome. He concluded that the smallerheaded spermatozoa contain the Y and the larger the X chromosome. These reports created a storm of rebuttal from biologists, zoologists, and microscopists around the world. Since these studies of Dr. Shettles' remain highly controversial, we felt that the Journal could serve a useful scientific purpose in attempting to crystallize the matter. Accordingly, we are publishing in the following pages the latest paper of Dr. Shettles, followed by a critique of his methods and findings by Dr. van Duijn, a biologist and microscopist of distinction. Dr. Shettles has had the opportunity of reading Dr. van Duijn's criticisms and his reply is included. THE EDITOR
REFERENCES 1.
SHETTLES,
L. B.
Nuclear morphology of human spermatozoa.
Nature 186:648,
1960. L. B. X and Y spermatozoa. Nature 187:524, 1960. L. B. Nuclear morphology of human spermatozoa. Obst. & Gynec. 16:10, 1960. 4. SHETTLES, L. B. Nuclear morphology of human spermatozoa. Med. Circle Bull. 7:8, 1960.
2. 3.
SHETTLES, SHETTLES,
501