Recent Advances in Human Genetics - Paper Presented at the Fifty-Fifth Annual Meeting

Advances in human genetics are taking place on several fronts; and despite the diversity of attacks on the problems involved, the author of this paper will limit himself to a few areas in which he and his students have either done some research or have a special interest. Every year some advances are being made in our knowledge of the inheritance of physical traits and an attempt will be made to briefly indicate some of the achievements and problems encountered in this field of study. The writer has been making a number of studies of the inheritance of physical traits

The Inheritance of Pitted Ear (Abstract)

Pitted ear is a relatively rare human anomaly defined as a pit in the proximal end of the upper part of the helix. This hereditary malformation has been studied in three different families, not known to be related. Pedigree charts prepared for these families show that one hundred and twenty-seven individuals are involved, of which twenty-four show pitted ear. This physical trait varies greatly throughout the families: the size of the pits ranges from approximately that of a pin head to about that of a match stick; and in depth, from about one-sixteenth to one-half inch. This trait is usually unilateral in its expression, but appears about as often in one ear as in the other; and there are some cases in which it is found in both ears. This character is not inherited as a simple Mendelian dominant, but rather an irregular dominance is suggested

The First Record of the Black Widow Spider (Lactrodectus mactans Texanus) for Iowa

There is great interest at the present time in the most poisonous of spiders, the black widow. This interest has been stimulated by the belief on the part of some biologists that its geographical range, which heretofore has been considered southern is being greatly extended. Scientific journals have been reporting the appearance of the black widow in states where it has not previously been found until on January 22, in Science, the statement was made that Minnesota and Iowa were the only states in which it had not been found. The writer believes that Iowa may be added to the black list

The Preparation of High School Science Teachers in Iowa

The Cooperative Committee on Science Teaching published a very interesting report entitled The Preparation of High School Science Teachers. This report pointed out that many of the science teachers in America are inadequately prepared for their jobs. The writer has long felt that that was particularly true of the Iowa science teachers. He has also been disturbed by the fact that our state requirements for certification of teachers were such that one .could teach high school biology with only five semester hours of college credit. The same thing is true for chemistry and physics. On the other hand, a language teacher must have ten semester hours, a mathematics teacher ten semester hours, and a commercial teacher five semester hours for each subject taught; for example, typing, shorthand, and bookkeeping. In addition to these subject matter requirements, a commercial teacher must have two semester hours in .commercial methods. Twenty semester hours are required for physical education, twenty-four semester hours for music, and thirty semester hours for art

The Time of Embryonic Determination of Sensoria and Antennal Color, and Their Relation to the Determination of Wings, Ocelli and Wing Muscles in Aphids

Intermediate-winged aphids of the species Macrosiphum solanifolii were studied in an effort to determine the time of embryonic segregation of the sensoria and antennal color, and their relation to the determination of wings, ocelli, and wing muscle. Dark antennal color and increased sensoria of winged aphids are considered to be characters closely correlated in development; for in general, when there was a darkening of antennae, there was a corresponding increase in the number of sensoria. In practically all cases increased sensoria were correlated with a relatively large amount of nondegenerate wing muscle. It is concluded that embryonic determination of dark antennal color and increased sensoria takes place in a comparatively short period of time as compared with that of wings, ocelli, and wing muscle. The data make it seem probable that while dark antennal color and extra sensoria, characteristic of winged aphid, arc determined after wings, ocelli, and wing muscle, they complete their segregation before that of the latter group

A Method of Mounting Diglycol Stearate Sections upon Slides (Abstract)

In the technique reported by Stiles and Eastwood (Iowa Acad. Sci. Proc. 1940) difficulty was encountered in floating Diglycol Stearate sections upon glass slides. The usual water albumen method of affixing ribbons upon slides could not be used satisfactorily for two reasons: first, because Diglycol is soluble in water, thus causing the ribbon to disintegrate before the tissue is permanently affixed to the slide and secondly because the surface tension of water causes a spreading effect of the ribbon. The difficulties of affixing the tissue to the slide when it is Diglycol embedded constituted a serious weakness in this technique. This investigation was undertaken in an attempt to find a floating agent which would not dissolve Diglycol ribbons in any appreciable amount. The use of calcium chloride as a floating agent was suggested by C. E. Moritz. Its solubility was tested in the usual manner, and it was found that Diglycol was not dissolved by it

Progress Report on a Survey of the Spiders of Iowa

The senior author began a study of Iowa spiders in the fall of 1936 when a black widow (Latrodectus mactaus texanus) was collected in Linn County. This was reported in Science (Stiles, 1937) and constituted the first official record of the black widow for Iowa. This record was of special interest because Minnesota and Iowa had been listed as the only states from which this spider had not been reported officially. It was discovered at that time that the spider was one of Iowa\u27s most neglected animals. Only three papers on our spider fauna have been reported to the Iowa Academy of Science in the past fifty years ; and there are no good collections of spiders in the State at the present time. In view of the incompleteness of our knowledge concerning Iowa\u27s spiders, it was thought worthwhile to begin a systematic study of them. It is the ambition of the Coe College Biology Department to make a study of the Araneae similar to that which Jaques (1932) is making on insects, thereby rounding out, somewhat, our knowledge of Iowa animal life. This is being undertaken with a full realization of the tremendous size of the task and the improbability that it will ever be wholly finished

The Effects of Mechanical Jarring upon the Embryogeny of Chick Embryos

The results of this study indicate that jarring at frequent intervals throughout the first day of incubation exerts a deleterious influence on the developing embryo. Only in one instance did an egg jarred from the fourth to the twelfth hour of incubation develop normally and hatch. Sixty per cent of the embryos thus jarred died sometime between the second and third day of incubation. The others ceased to develop between the third and eleventh day of incubation

Studies on Iowa Spiders

The spiders reported in this paper were collected by Professor H. E. Jaques and his students in the summer of 1940. From this collection twenty-five species and fifteen genera representing seven different families have been determined. Of the one hundred and twenty-eight \u27individuals reported, there are sixty-three males, sixty-three females, and two immature. These spiders came from twenty-nine counties; their geographical distribution is indicated in Plate 1. All determinations were checked by W. J. Gertsch of the American Museum of Natural History, New York City, and it is a pleasure for the authors to acknowledge their appreciation of Dr. Gertsch\u27s assistance. It is believed that this report includes many of the more common species of Iowa spiders and, therefore, should be of special assistance to high school teachers and pupils interested in the identification of these interesting animals. The families as well as the species are briefly described. Furthermore, several simple figures, a brief glossary of terms, and a bibliography are included for the benefit of beginning students of spiders

A Bovine Monstra Duplica

Double monsters are pathological deviants from identical twins, in that the embryos are joined in some manner. The embryos may be symmetrically united and developed, or one of the individuals may he arrested in its development. In describing the morphological relationships of the calf of this study, the right and left sides will refer to the animal\u27s right and left respectively. From a superficial examination of this specimen it appears to be a single-bodied calf with two heads, an extra leg with two hooves protruding from the hack a short distance caudal to the vertex of the two heads, and two tails. These facts indicate that there are two animals in this union, hut this indication is not carried out on the ventral surface as there are only four teats and one opening for the umbilical vessels to enter the body