Showing papers by "University of Virginia published in 1978"

Patterns of Attachment: A Psychological Study of the Strange Situation

Abstract: Part I: Introduction 1. Theoretical Background Part II: Method 2. Procedures 3. Measures and Methods of Assessment Part III: Results 4. Descriptive Account of Behavior in Each Episode 5. Normative Trends across Episodes 6. An Examination of the Classificatory System: A Multiple Discriminate Function Analysis 7. Relationships between Infant Behavior in the Strange Situation and at Home 8. Relationships between Infant Behavior in the Strange Situation and Maternal Behavior at Home 9. A Review of Strange-Situation Studies of One-Year-Olds 10. A Review of Strange-Situation Studies of Two- to Four-Year-Olds 11. The Effects of Repetition of the Strange Situation 12. Subgroups and Their Usefulness Part IV: Discussion 13. Discussion of Normative Issues 14. Individual Differences: In Light of Contrasting Paradigms 15. An Interpretation of Individual Differences Appendix I: Instructions to Mother Appendix II: Instructions for Coding and Tabulating Frequency of Behaviors Appendix III: Scoring System for Interactive Behaviors Appendix IV: Maternal Caregiving and Interaction Scales Appendix V: Secure Base Behavior At Home Appendix VI: Supplementary Statistical Findings

The afferent connections of the main and the accessory olfactory bulb formations in the rat: an experimental HRP-study.

Abstract: The afferent connections of the main and accessory olfactory bulbs in the rat were examined by injecting horseradish peroxidase (HRP) into one or the other of these structures either by microelectrophoresis or by hydraulic pressure. Alternate sections were stained with newly developed HRP-procedures using either benzidine dihydrochloride (de Olmos and Heimer, '77) or tetramethyl-benzidine. Eighteen to twenty-four hours after unilateral HRP injections confined to the main olfactory bulb, a large number of HRP-labeled perikaria appeared in the following telencephalic structures on the ipsilateral side: All portions of the anterior olfactory nucleus (AON) except its external part, the lateral transitional field (LT) between AON and the paleocortex, the whole extent of the primary olfactory cortex (POC); The medial forebrain bundle area deep to the olfactory tubercle, the nucleus of the horizontal limb of the diagonal band (NHDB) and the nucleus of the lateral olfactory tract (NLOT). A moderate to small number of labeled cells, furthermore, were seen in the dorsal (DT) and medial (MT) transition fields, the ventral praecommissural hippocampus (tt2), the ventral superficial part of the nucleus of the vertical limb of the diagonal band (NVDB), the sublenticular part of the substantia innominata (SI), the anterior amygdaloid area, the posterolateral cortical amygdaloid nucleus (C2) and the transition region (28 L') between the olfactory cortex and the lateral entorhinal area proper. On the contralateral side a large number of labeled cells were found in all parts of the AON, with especially heavy labeling in its external part. A moderate number of labeled cells could also be detected in the lateral transition field (LT) and the NLOT. In the diencephalon and the brain stem a moderate number of HRP-labeled perikaria were observed in the dorsal, perifornical, and lateral hypothalamus, as well as in locus coeruleus and the dorsal and medial raphae nuclei. Following large HRP injections in the main olfactory bulb a moderate to small number of labeled cells were seen also in the posterior and premammillary hypothalamus and in field CA1 of the retrocommissural hippocampus on the ipsilateral side, as well as in POC on the contralateral side. It is possible, however, that the uptake of label took place in an undetected pool of HRP in the very rostral part of AON rather than in the olfactory bulb. HRP injections in the accessory olfactory bulb resulted in labeled neurons in the posterior ventro-lateral part of the bed nucleus of the stria terminalis, the nucleus of the accessory olfactory tract, the rostrodorsal portions of the medial amygdaloid nucleus, and whole extent of the posteromedial cortical amygdaloid nucleus (C3) on the ipsilateral side. A few lightly labeled cells were seen also in the contralateral C3.

On The Computation of Equivalent Potential Temperature

Abstract: The computation of θE, the pseudo-quivalent potential temperature, ordinarily omits the contribution due to specific heats of water vapor. This may he an acceptable practice for temperate-latitude usages but a questionable one when applied in the tropics where lower layers, rich in moisture, may he several; degrees warmer and the vertical gradient larger when this factor is included. An inexpensive method of computing θE to include the beat capacities of water substance is presented aid the results compared with those derived from several tephigrams which ignore this contribution.

A Theory of Job Shopping

Abstract: I. Introduction, 261.—II. The basic model—risk neutrality, 262.—III. Mobility cost, 268.—IV. Education, 270.—V. Extensions of the basic model, 272.—VI. Empirical applications, 274.

Role of cyclic GMP in the action of heat-stable enterotoxin of Escherichia coli.

Abstract: ENTEROTOXIGENIC strains of Escherichia coli elaborate two enterotoxins, a heat-labile toxin (LT) and a heat-stable toxin (ST), which cause diarrhoeal disease in humans1; ST-producing E. coli cause diarrhoea in adult volunteers2 and have been associated with epidemic diarrhoea in a nursery for the newborn3 and with sporadic adult diarrhoea among North American tourists to Latin America4 and the Navajo people in Arizona5. LT-producing strains are identified by the ability of culture filtrates to cause fluid accumulation in rabbit ileal loops at 18 h (ref. 6) or by morphological alteration of Chinese hamster ovary (CHO) cells7 or of Y-l adrenal cells8. ST-producing strains are identified by the ability of culture filtrates to cause earlier fluid accumulation in rabbit ileal loops (peak accumulation at 6 h (ref. 6), or by fluid accumulation in the gut of the suckling mouse at 3 h (refs 9, 10). LT acts in a manner similar to cholera toxin (CT) by activating adenylate cyclase11. The mechanism of action of ST is unknown, however. Culture filtrates of a strain of E. coli that produced both LT and ST caused immediate net fluid secretion in canine jejunal segments without the 1-h delay characteristic of the response to CT12,13. In addition, culture filtrates caused an immediate increase in canine jejunal adenylate cyclase activity as measured by enzymatic generation of P32-cyclic AMP from P32-labelled ATP13, also in contrast to the delay in appearance of increased adenylate cyclase activity following exposure to CT12. The possibility that the early effect of ST was mediated by changes in cyclic nucleotide concentrations was investigated; culture filtrates of ST-producing strains of E. coli caused increased cyclic GMP concentrations in rabbit intestinal tissue and the cyclic GMP analogue 8BrcGMP mimicked ST in magnitude and time course of intestinal fluid accumulation in both rabbits and suckling mice.

Statistical mechanical deconvolution of thermal transitions in macromolecules. I. Theory and application to homogeneous systems

Abstract: The theoretical basis for the statistical mechanical deconvolution of a thermally induced macromolecular melting profile is presented. It is demonstrated that all the thermodynamic quantities characterizing a multistate macromolecular transition can be obtained from the average excess enthalpy function, 〈ΔH〉, of the system, without any assumption of the particular model or mechanism of the reaction. Experimentally, 〈ΔH〉 is obtained from scanning calorimetric data by direct integration of the excess apparent molar heat capacity function, ΦCp. Once 〈ΔH〉 is known as a continuous function of the temperature, the partition function, Q, of the system can be calculated by means of the equation From the partition function all the thermodynamic quantities of the system can be obtained. It is shown that the number of discrete macroscopic energy states, the enthalpy and entropy changes between them, and the relative population of each state as a function of temperature can be calculated in a recursive form.

Benzodiazepines specifically modulate GABA-mediated postsynaptic inhibition in cultured mammalian neurones

Abstract: BENZODIAZEPINES (BDZ) such as diazepam (DZ) and chlordiazepoxide (CDZ) are commonly used anticonvulsants, muscle relaxants, antianxiety agents and hypnotics. The cellular mechanisms underlying these clinically important effects have not been established, but attention has been focused on the effect of BDZ on pre- and postsynaptic responses to the putative neurotransmitter amino acids, specifically glycine (Gly)1,2 and γ-aminobutyric acid (GABA)3–7. An effect of BDZ on postsynaptic Gly receptors was suggested by the finding that BDZ reduce strychnine binding to central nervous system (CNS) synaptic membrane fractions in vitro2, but physiological studies, in vivo, have provided little support for such an interaction with Gly3. BDZ have been reported (1) to facilitate presynaptic inhibition in the spinal cord4,5, at least partially GABA-mediated8–10; (2) to facilitate GABA-mediated pre- and postsynaptic inhibition in the cuneate nucleus6; (3) to mimic the presynaptic action of GABA on preganglionic nerve terminals12, and (4) to antagonise13,14 and to enhance15,16 the postsynaptic action of GABA on CNS neurones. It has also been suggested that BDZ alter GABA metabolism4,5 or mobilise GABA from neuronal storage sites17, and BDZ have been demonstrated to bind specific receptors on synaptosomal membrane preparations derived from rat brain18, an effect which is independent of amino acid receptors. Thus, it is uncertain whether BDZ action is GABA or Gly receptor-mediated, due to an alteration of GABA metabolism, or due to direct binding to a specific receptor which binds BDZ. We have studied the effect of DZ and CDZ on amino acid-mediated postsynaptic responses in cultured mammalian spinal cord neurones and report that the BDZ selectively modify GABA-mediated postsynaptic inhibition in a dose-dependent fashion, augmenting the response at low doses and antagonising the response at higher doses.

Multiple Resource–Constrained Scheduling Using Branch and Bound

Abstract: This paper focuses upon the problem of assigning feasible start times to a set of activities making up a project, static job shop, or static flowship type schedules under two constraint sets: (1) no activity may be started until all activities technologically established as its predecessor set have been completed, and (2) the total resource requirements of all activities in process at any time in the schedule must not exceed the level of availability for each of the multiple resource classes. The solution procedure used for these problems is branch and bound, and the resulting complete schedules are optimized with an objective of minimizing the completion time of the entire set of activities. Computational results on tests conducted on a number of randomly generated problem sets with up to 60 activities and six resource classes are presented.

Eating Meat and Eating People

Abstract: This paper is a response to a certain sort of argument defending the rights of animals. Part I is a brief explanation of the background and of the sort of argument I want to reject; Part II is an attempt to characterize those arguments: they contain fundamental confusions about moral relations between people and people and between people and animals. And Part III is an indication of what I think can still be said on—as it were–the animals' side.

Superior colliculus connections with the extraocular motor nuclei in the cat

Abstract: Direct and indirect projections from the cat superior colliculus to the extraocular motor nuclei were studied using the orthograde autoradiographic tracing method, the retrograde horseradish peroxidase technique, and Golgi methods. The results show that the superior colliculus projects to the central gray matter directly overlying the oculomotor complex. This projection arises almost entirely from the rostral third of the colliculus, and it terminates most heavily over the rostral half of the oculomotor complex. Dendrites of oculomotor cells extend into this tectal termination zone, making direct tecto-oculomotor contacts possible. Central gray cells within this termination zone project bilaterally to the abducens nuclei. It is proposed that the superior colliculus projection to the supraoculomotor central gray matter and the projection from the central gray matter to the abducens nuclei play a role in convergent eye movements. The superior colliculus projects lightly to a cell group directly ventrolateral to the trochlear nucleus. The superior colliculus sends a small direct projection to the contralateral abducens nucleus and a substantial projection to wide regions of the reticular formation that have been shown previously to project, in turn, to the abducens nucleus. Colliculus cells projecting to the abducens nucleus and adjacent reticular formation are located only in the caudal three-fourths of the colliculus, where they become increasingly concentrated at successively more caudal levels. It is proposed that the graded density of the cells of origin of this projection is the basic structural mechanism by which the colliculus generates horizontal foveating saccades of different amplitudes. Laminar analysis of the origin of all the superior colliculus projections to the extraocular motor regions described here revealed that they arise mostly from the stratum griseum intermedium.

Hormonal growth control of cells in culture

Abstract: Serum is the last undefined component in cell culture media. Our results indicate that the primary role of serum is to provide hormones and that serum can be replaced by a group of hormones. A rat pituitary cell line, GH3, can grow in serum-free medium if the medium is supplemented with 3,3′,5-triiodothyronine, TSH-releasing hormone, transferrin, parathyroid hormone, insulin and three isoelectric focusing fractions of blood meal. The blood-meal components can be replaced by fibroblast growth factor and somatomedin C. The growth rate of GH3 cells in hormone-supplemented serum-free medium is equal to that in serum-supplemented medium, and subculture in such medium is also possible. These results indicate that the replacement of the serum component is complete in the GH3 system. The hormonal requirements of GH3 cells and those of HeLa and mouse melanoma, M2R, were compared. Two generalizations could be made: (a) All three cell lines require insulin and transferrin. (b) There is a requirement for a hormone which localizes in the nucleus for each cell line. These generalizations seem to hold true for most of the other cell lines for which the hormonal requirements have been partially worked out. Since insulin is one of the universally required hormones, its effects on GH3, HeLa and M2R were compared. Insulin stimulates glycogen synthesis in all three cell lines and facilitates fatty-acid synthesis in GH3 and M2R. However, there is a difference in the effect of insulin on growth among the three cell lines. Insulin is an absolute requirement for GH3 cells without which the cells cannot survive, whereas this is not the case for HeLa and M2R. The most stringent requirement for HeLa cells is for hydrocortisone, and for M2R, it is for transferrin. These results indicate that even though the necessity for some hormones is common, the degree of requirement may vary from one cell line to another. Whether this difference reflects the difference in the primary mode of action of the hormone on each cell type needs further investigation.

The collection of precipitation for chemical analysis

Abstract: This paper is one of a series of publications on the collection and chemical analysis of precipitation. While the first paper presented the results from an intercalibration of 10 different designs of precipitation collectors (Galloway and Likens, 1976), this paper presents results of experiments on the collection efficiency of collectors, preservation of samples, monthly variation of wet and dry deposition, sample storage, length of sampling period, choice of collector location and sources of variability in precipitation data. The primary conclusions are that dry fallout should usually be excluded from rain and snow samples, sampling should be on an event basis, all biocides tested have some detrimental effect on sample composition, and that the major sources of variability in precipitation data are due to sampling errors and choice of collector location. DOI: 10.1111/j.2153-3490.1978.tb00819.x

Adenosine production in the ischemic kidney.

Abstract: We conducted experiments to determine (1) tissue, blood, and urine levels of adenosine produced by the ischemic kidney under conditions of renal artery occlusion, and (2) the site(s) of production and release of adenosine by the kidney. Concentrations of adenosine, inosine, and hypoxanthine in the dog urine were found to increase after 2 minutes of renal artery occlusion as were concentrations of these metabolites in renal tissue after 10 minutes of renal artery occlusion. Renal venous plasma levels of inosine and hypoxanthine also were elevated after 3 minutes of arterial occlusion. In modified stop-flow experiments, adenosine appeared in the urine in a peak that corresponded most closely with proximal tubule fluid. 5'-Nucleotidase, the enzyme which catalyzes the dephosphorylation of 5'-AMP or 5'-IMP to adenosine or inosine, respectively, was found to be located primarily on the external membranes and mitochondria of proximal tubule cells, but not in distal tubule or collecting duct cells. Since adenosine has been demonstrated to elicit renal vasoconstriction and is produced by the ischemic kidney, it is suggested that adenosine may be involved in the mediation of postocclusion renal ischemia.

The superior colliculus control of pinna movements in the cat: Possible anatomical connections

Abstract: Possible anatomical pathways mediating superior colliculus control of pinna movements were determined in the cat using the orthograde autoradiographic tracing method and the retrograde horseradish peroxidase technique This was done in the following manner First, the division of the facial nucleus that innervates the pinna muscles was determined by injecting the pinna muscles with HRP and surveying the facial nucleus for retrogradely filled cells Second, the brainstem regions that project the facial nucleus were identified using the horseradish peroxidase method Third, the superior colliculus projections to these areas were studied using the autoradiographic tracing method The results suggest that superior colliculus control of pinna movements is mediated entirely by indirect connections with the facial nucleus and that these connections occur mainly in a paralemniscal zone in the lateral midbrain Of all the brainstem regions shown by the horseradish peroxidase experiments to project to the facial nucleus only this midbrain paralemniscal zone received a projection from the superior colliculus that was dense and overlapped precisely the region containing facial projecting neurons Further autoradiographic tracing revealed that the facial nucleus was the primary brainstem target of this paralemniscal zone and that all paralemniscal fibers projecting to the facial nucleus ended in the subdivision that innervates the pinna muscles Other paralemniscal efferents terminate in the opposite paralemniscal zone The data suggest that other connections between the superior colliculus and the facial nucleus may occur in the cuneiform nucleus of the midbrain, the region around the oculomotor complex, and the reticular formation dorsal to the superior olive

Band structure and superconductivity of Pd D x and Pd H x

Abstract: A study of the electronic band structure of the pailadium-hydrogen system was made using the augmented-plane-wave method. The calculations were performed self-consistently for two choices of the exchange parameters within the $X\ensuremath{\alpha}$ scheme. Spin-independent relativistic corrections were included explicitly. The results for the energy bands are compared with previous calculations. Our results are found to be in good agreement with photoemission measurements. The calculations of the superconducting properties of this system are studied as a function of hydrogen content, utilizing the theory of Gaspari and Gyorffy and neutron-scattering data. The results for the superconducting transition temperature ${T}_{c}$ are in very good agreement with the measured values. An analysis of these results attributes the observed inverse isotope effect to the effective increase of the Pd-H force constant over the Pd-D force constant, due to enhanced anharmonicity of the H motion, as originally proposed by Ganguly.

Specific-opiate-induced depression of transmitter release from dorsal root ganglion cells in culture.

Abstract: The opiate etorphine depresses monosynaptic excitatory postsynaptic potentials (EPSP's) elicited in spinal cord cells by activation of dorsal root ganglion cells in murine neuronal cell culture. The depression is reversed by naloxone. Statistical analysis of the synaptic responses reveals that the opiate reduces EPSP quantal content at this synapse without altering quantal size. Therefore, the opiate action is presynaptic and affects transmitter release rather than postsynaptic responsiveness.

Coronary-prone behavior pattern and cardiovascular response.

Abstract: Two studies were carried out examining the relationship between coronary-prone behavior pattern and cardiovascular responses to an experimental stressor. Among 52 subjects of the Type A (coronary-prone) and Type B (non-coronary-prone) behavior patterns in Study I, Type A males showed greater elevations of systolic blood pressure than Type B males on exposure to a difficult cognitive task; no reliable differences were found for Type A and B females. Due to a conceptual similarity of the coronary-prone behavior pattern and the personality dimension of Internal External locus of control, 48 male subjects in Study II were selected with respect to four subject groups: Type A-Internals, Type A-Externals, Type B-Internals, and Type B-Externals. Again, Type As showed a more pronounced systolic response than subjects of the Type B pattern, though diastolic blood pressure and heart rate responses did not vary by coronary-prone behavior pattern. While locus of control-Internals tended to show greater task-related systolic elevations than Externals, this effect was not significant. Self-reports of anxiety increased during the period of the task, but revealed no differences among Type A and B subjects of either study. It was concluded that for male subjects the Type A-Type B dimension constitutes a salient variable of individual differences mediating the systolic pressor response.

Elastic Electron Scattering from He 3 and He 4 at High Momentum Transfer

Abstract: Experimental values of $^{3}\mathrm{He}$ ($^{4}\mathrm{He}$) elastic structure functions up to momentum transfer ${q}^{2}=4.0 (2.4)$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ are presented. They are compared to calculations using three- and four-body wave functions and to asymptotic models.

Sand transport model of barchan dune equilibrium

Abstract: Erosion and deposition over a barchan dune near the Salton Sea, California, is modelled by book-keeping the quantity of sand in saltation following streamlines of transport. Field observations of near-surface wind velocity and direction plus supplemental measurements of the velocity distribution over a scale model of the dune are combined as input to Bagnold-type sand-transport formulae corrected for slope effects. A unidirectional wind is assumed. The resulting patterns of erosion and deposition compare closely with those observed in the field and those predicted by the assumption of equilibrium (downwind translation of the dune without change in size or geometry). Discrepancies between the simulated results and the observed or predicted erosional patterns appear to be largely due to natural fluctuation in the wind direction. Although the model includes a provision for a lag in response of the transport rate to downwind changes in applied shear stress, the best results are obtained when no delay is assumed. The shape of barchan dunes is a function of grain size, velocity, degree of saturation of the oncoming flow, and the variability in the direction of the oncoming wind. Smaller grain size or higher wind speed produce a steeper and more blunt stoss-side. Low saturation of the inter-dune sandflow produces open crescent-moon-shaped dunes, whereas high saturation produces a whaleback form with a small slip face. Dunes subject to winds of variable direction are blunter than those under unidirectional winds. The size of barchans could be proportional to natural atmospheric scales, to the age of the dune, or to the upwind roughness. The upwind roughness can be controlled by fixed elements or by the sand is saltation. In the latter case, dune scale may be proportional to wind velocity and inversely proportional to grain size. However, because the effective velocity for transport increases with grain size, dune scale may increase with grain size as observed by Wilson (1972).

Fluorescence and calorimetric studies of phase transitions in phosphatidylcholine multilayers: kinetics of the pretransition.

Abstract: Discrepancies between calorimetric and fluorescence depolarization monitoring of the pretransition in multilamellar vesicles of synthetic phosphatidylcholines are shown to result primarily from the slow rate of this transition. The depolarization of fluorescence of the membrane-associated dye 1,6-diphenyl-1,3,5-hexatriene was used to determine the temperature of the pretransition for a series of heating and cooling scan rates. These temperatures, when plotted vs. scan rate, extrapolated linearly to the transition temperature at zero-scan rate, Tm = 29.8 +/- 0.8 degrees C. The slopes obtained from these plots yielded characteristic times for the transition of 8 to 30 min. In addition, analysis of temperature-jump experiments, assuming first-order kinetics, gave characteristic times in the range 4--8 min. The data are taken to suggest a most likely value for the pretransition characteristic time of 5 +/- 2 min, with larger values possibly explainable by supercooling effects. Slight differences between the calorimetrically and fluorimetrically determined main transition temperatures appear to result from perturbation of the phosphatidylcholine bilayer by the fluorescent probe.

Rapid transneuronal degeneration and death of cortical neurons following removal of the olfactory bulb in adult rats.

Abstract: Following olfactory bulb removal in young and adult rats, many neurons in the primary olfactory cortex become markedly argyrophilic in silver impregnated preparations. Although argyrophilic neurons are found scattered throughout the pyramidal and multiform cell layers, the heaviest concentration is seen in the superficial part of the pyramidal layer. Electron microscopic analysis reveals that argyrophilic neurons are undergoing rapid degeneration. The degenerative changes are similar in all affected cells, although some cells begin to disintegrate within 24 hours following bulbectomy, whereas others are just beginning to show pathological changes at three or four days. The first clear signs of cellular degeneration occur in the cytoplasm of the perikaryon and involve swelling of mitochondria and polysome disaggregation. An increase in the electron density of the cytoplasm follows and this is accompanied by the appearance of enlarged cisternae and disruption of the nuclear membrane. Degenerative changes in the nucleus usually are detected at a slightly later stage than in the cytoplasm. Nuclear changes are characterized by the proliferation of local aggregations of condensed chromatin, and the replacement of the nucleolus with large homogenous islands of electron dense material. In advanced stages of degeneration ribosomes are increased in density and become uniformly dispersed throughout the cytoplasm. Remnants of necrotic organelles are visible only at the cellular periphery, and phagocytosis of dying neurons by astrocytes and microglia follows quickly. Evidence from HRP-studies indicates that cells in the olfactory cortex, which project directly to the bulb do not correspond to those which show fulminant necrosis following olfactory bulb removal. The majority of those which degenerate are located superficially, whereas the cells of origin of the centrifugal projection lie more deeply. Based on this dissociation, it is proposed that rapid cell death in the olfactory cortex is not caused by retrograde factors involving axotomy, but is due instead to transneuronal deafferentation that results from a sudden massive loss of input from the olfactory bulb.

Is sex determination in germ line and soma controlled by separate genetic mechanisms

Abstract: IN sexually dimorphic animals, the determination of sex is a major branch point in development. Although mutations producing sex reversal shed some light on the processes by which this determination is reached, many questions remain unanswered. Autosomal mutations such as polled in the goat1, sex reversed (Sxr)2 in the mouse and transformer (tra)3,7 in Drosophila cause chromosomal females to become phenotypic males, although they are sterile and their gonads agametic. The nature of this sterility suggests that the sex of germ cells in Drosophila, and perhaps in other species, might be determined by different sets of genes from those which operate in somatic tissue. Here we test this hypothesis by constructing mosaics in Drosophila where germ cells of one genotype are surrounded by soma of another. We find that the transformer mutation affects only the somatic sexual differentiation, and that it has no effect on the differentiation of germ cells. Thus we conclude that the agametic nature of transformed flies is due to the absence of functional male germ cells and at least with respect to tra, germ line and soma have separate sex-determining genes.