A Magnetometer Survey of the Knife River Indian Villages

Abstract

There are several Indian village sites at the confluence of the Knife and Missouri rivers near the town of Stanton, North Dakota. Two of them were examined or tested by D. J. Lehmer in 1965. Four of the sites are now being incorporated into the Knife River Indian Villages National Historic Site. As part of the development of this Historic Site a proton magnetometer survey was carried out in 1976 on parts of Sakakawea Village and the Buchfink Site. In addition, a survey was conducted on part of the Amahami Village in Stanton. This article discusses the theory of magnetic surveying, the varying nature of the regions surveyed, and the extensive results abtained. These results include the identification of at least 12 earth lodge sites with associated features, the correlation of some features in the magnetic data with soil probe information, and a number of suggestive but unidentifed features on which the magnetic measurements focus.     

An Unusual Method of Flint Chipping

Abstract

Three ethnographic examples, two from the Plains and one from Australia, of the process of sharpening chipped stone tools with the teeth are noted.     

The Control of Inter-pollination between Sweet and Flint Corn

The breeding system of sweet corn, a sugary seeded race of Zeamays L., was studied by randomly planting equal numbers of sweetand flint plants and determining the amount of cross-pollinationmeasured by the contamination on sweet ears. It was found thatinter-crossing with flint varied significantly from plant toplant; the out-crossing generally was lower than anticipated.The effects of date of silking and tasselling, and protandryof sweet plants on their out-crossing was demonstrated by usingmultiple regression analysis. Even so, as prediction was stillnot satisfactory other factors must have been involved. Thesevariables were all highly correlated. A relation between contaminationand temporal isolation was established; this was similar tothat for spatial isolation. It was postulated that there mayhave been genetical control of inter-pollination, as later earson the same sweet-corn plants were not less contaminated thanearlier ones and because out-crossing was generally low throughoutthe experiment.     

A Thermoelectrically Cooled Microtome Table and Knife

Thermoelectric cooling units (Frigistor thermoelements) have been used to replace CO₂ gas and solid CO₂ for microtome stage and knife cooling. These units consist of assemblies of series-connected thermoelements, functioning by the Peltier effect. Cooling is controlled by the direct current supply to the units. Current supply is from a double power pack giving 15 amp at 4.8 v for the knife cooling units, and 15 amp at 1 v for the stage. By varying the current flow, the optimum cutting temperature can be obtained and held indefinitely. An 8-couple Frigistor unit replaces the CO₂ stage of a Lipshaw freezing microtome. The stage temperature may be lowered to -36 C in 40-60 sec and at the optimum cutting temperature, 5 μ serial sections of fixed frozen tissue are obtainable. Four 12-couple units are used to cool a 160 mm Jung plane wedge microtome knife fitted to a Reichert sledge microtome, with the stage cooled by one 8-couple unit. The knife temperature can be lowered to -20 C in 5 min; the stage in 1 min. The apparatus has been used to cut a variety of unfixed rat and mouse tissues. The optimum sectioning temperature for such unfixed liver, kidney, spleen, lymph glands, heart, testes, small intestine, pancreas, skin and lung was -20 to -22 C.     

European Flint Landraces Grown In Situ Reveal Adaptive Introgression from Modern Maize

We have investigated the role of selection in the determination of the detected levels of introgression from modern maize hybrid varieties into maize landraces still cultivated in situ in Italy. We exploited the availability of a historical collection of landraces undertaken before the introduction and widespread use of modern maize, to analyse genomic changes that have occurred in these maize landraces over 50 years of co-existence with hybrid varieties. We have combined a previously published SSR dataset (n=21) with an AFLP loci dataset (n=168) to provide higher resolution power and to obtain a more detailed picture. We show that selection pressures for adaptation have favoured new alleles introduced by migration from hybrids. This shows the potential for analysis of historical introgression even over this short period of 50 years, for an understanding of the evolution of the genome and for the identification of its functionally important regions. Moreover, this demonstrates that landraces grown in situ represent almost unique populations for use for such studies when the focus is on the domesticated plant. This is due to their adaptation, which has arisen from their dynamic evolution under a continuously changing agro-ecological environment, and their capture of new alleles from hybridisation. We have also identified loci for which selection has inhibited introgression from modern germplasm and has enhanced the distinction between landraces and modern maize. These loci indicate that selection acted in the past, during the formation of the flint and dent gene pools. In particular, the locus showing the strongest signals of selection is a Misfit transposable element. Finally, molecular characterisation of the same samples with two different molecular markers has allowed us to compare their performances. Although the genetic-diversity and population-structure analyses provide the same global qualitative pattern, which thus provides the same inferences, there are differences related to their natures and characteristics.     

An Improved Diamond Knife Holder for Ultramicrotomy

A simple sensitive and specific cytochemical method for detection of the Y chromosome in man (George 1970, Pearson et al. 1970) is based on staining by alkylating fluorochromes. The dye binds strongly to the heterochromatic regions of the Y chromosome, thus causing these regions to fluoresce very brightly under ultraviolet (uv) light. The Y chromosome could be identified easily at metaphase and also as a highly fluorescent body in interphase cells. Two bodies were seen by Pearson et at. in a subject having the XYY anomaly. In prophase cells, it appears as a fluorescing chromatin thread. Its presence has been demonstrable only in males; hence the usefulness of this technique for rapid cytogenetic screening is obvious. The constancy and reproducibility of the technique seems to rule out the possibility of unreliability caused by nonspecific binding of the dye. The present report gives techniques applied to tissues usually studied in cytogenetic screening