Effect of four mutations (Cr,S,S(H),h) in genes for mink coat color on brain monoamine oxidase]

Activity of A and B types of monoamine oxidase (MAO) has been investigated in the brain stem and brain hemispheres of mink males of five genotypes for coat-color mutations: standard dark-brown (+/+); heterozygous for the semidominant mutation Black crystal (Cr/+); homozygous for the semidominant mutation Black cross, or "95% White" (S/S); heterozygous for the semidominant mutation Shadow (SH/+); and homozygous for the semirecessive mutation hedlum white (h/h). The main changes in the activity of the A and B MAO types occur in the brain hemispheres. A reduced activity of MAO A has been recorded in the hemispheres of Black crystal minks (Cr/+) and an elevated activity, in the hemispheres of Shadow (SH/+) and 95% White (S/S). The activity of MAO B is reduced in the hemispheres of Black crystal and elevated in the hemispheres of hedlum white (h/h). An increased MAO A activity has also been recorded in the brain stem of Shadow minks (SH/+). It is suggested that genes controlling coat color have a pleiotropic effect on sexual behavior in males and the endocrine function of testicles mediated by a putative change in the metabolism of brain neurotransmitters, substrates of MAOs A and B.     

Interplay between aggression,brain monoamines and fur color mutation in the American mink

Domestication of wild animals alters the aggression towards humans, brain monoamines and coat pigmentation. Our aim is the interplay between aggression, brain monoamines and depigmentation. The Hedlund white mutation in the American mink is an extreme case of depigmentation observed in domesticated animals. The aggressive (?2.06 ± 0.03) and tame (+3.5 ± 0.1) populations of wild‐type dark brown color (standard) minks were bred during 17 successive generations for aggressive or tame reaction towards humans, respectively. The Hedlund mutation was transferred to the aggressive and tame backgrounds to generate aggressive (?1.2 ± 0.1) and tame (+3.0 ± 0.2) Hedlund minks. Four groups of 10 males with equal expression of aggressive (?2) or tame (+5) behavior, standard or with the Hedlund mutation, were selected to study biogenic amines in the brain. Decreased levels of noradrenaline in the hypothalamus, but increased concentrations of the serotonin metabolite, 5‐hydroxyindoleacetic acid and dopamine metabolite, homovanillic acid, in the striatum were measured in the tame compared with the aggressive standard minks. The Hedlund mutation increased noradrenaline level in the hypothalamus and substantia nigra, serotonin level in the substantia nigra and striatum and decreased dopamine concentration in the hypothalamus and striatum. Significant interaction effects were found between the Hedlund mutation and aggressive behavior on serotonin metabolism in the substantia nigra (P < 0.001), dopamine level in the midbrain (P < 0.01) and its metabolism in the striatum (P < 0.05). These results provide the first experimental evidence of the interplay between aggression, brain monoamines and the Hedlund mutation in the American minks.     

Effect of Four Coat Color Mutations (Cr,S, SH,and h) on Brain Monoamine Oxidase in Mink

Activity of A and B types of monoamine oxidase (MAO) has been investigated in the brain stem and brain hemispheres of mink males of five genotypes for coat color mutations: standard dark-brown (+/+); heterozygous for the semidominant mutation Black crystal(Cr/+); homozygous for the semidominant mutation Black cross, or 95% White (S/S); heterozygous for the semidominant mutationShadow(S ^H/+); and homozygous for the semirecessive mutation hedlund white(h/h). The main changes in the activity of the A and B MAO types occur in the brain hemispheres. A reduced activity of MAO A has been recorded in the hemispheres of Black crystalminks (Cr/+) and an elevated activity, in the hemispheres of Shadow(S ^H/+) and 95% White(S/S). The activity of MAO B is reduced in the hemispheres of Black crystaland elevated in the hemispheres of hedlund white(h/h). An increased MAO A activity has also been recorded in the brain stem of Shadowminks (S ^H/+). It is suggested that genes controlling coat color have a pleiotropic effect on sexual behavior in males and the endocrine function of testicles mediated by a putative change in the metabolism of brain neurotransmitters, substrates of MAOs A and B.     

Gonadal and adrenal endocrine functions in female minks of 2 genotypes in postnatal ontogeny

Radioimmune assay has been made of the content of estradiol and progesterone in the blood (from July to March including the 7th day after mating), as well as on the level of estradiol and progesterone production in young females of the standard and mutant sapphire minks in November. It was shown that within certain periods, estradiol and progesterone content of the blood was significantly higher in the standard animals. Gonadal production of estradiol, as well as progesterone production both by the gonads and adrenals in November, were similar in females of both genotypes. It is suggested that sapphire minks have another pattern of correlation between estradiol content of the blood and gonadal production of estradiol as compared to that in standard animals.     

Linear dose-response relationship of erythrocyte enzyme-activity mutations in offspring of ethylnitrosourea-treated mice

The specific activity of 10 erythrocyte enzymes was measured to detect gene mutations in F1 offspring of male mice treated with 3 different doses of ethylnitrosourea (ENU). After administration of ENU or of the solvent (controls), the (101/El X C3H/El)F1 hybrid males were mated to untreated T-stock females. No enzyme-activity mutant was found in 3610 F1 offspring of the control group. After treatment of postspermatogonial germ-cell stages, 1 mutant in 1125 F1 offspring of males treated with 160 mg ENU/kg body weight, and 2 mutants in 1319 F1 offspring of a 250-mg/kg group were observed. After treatment of spermatogonia, 9 enzyme-activity mutants in 4247 F1 offspring of males treated with 80 mg ENU/kg body weight, 15 mutants in 3396 F1 offspring of a 160-mg/kg group, and 9 mutants in 1402 F1 offspring of a 250-mg/kg group were detected. The mutation frequencies in spermatogonia were significantly different from that of the controls (P less than 0.01). The dose-response curve was found to be linear. The frequencies of enzyme-activity mutations are comparable to those of recessive specific-locus mutations determined in the same experiments. Enzyme-activity mutants with reduced activity as well as mutants with enhanced activity were found. Genetic and biochemical characterization of enzyme-activity mutants was routinely performed. In inter se crossings of heterozygotes, no offspring expressing a third phenotype other than the wild type and the heterozygote were found in approximately half of the mutation studies. The recovered mouse mutants might be used as animal models to study corresponding genetic diseases in humans.     

Effect of color mutation on the function of the adrenal cortex in chronic feed stress in American mink

Effect of color mutations, headlund and aleutian, on the adrenocortical function was studied in American mink under stress conditions. The adrenocortical function was analysed in the course of gland's incubation in vitro. Natural environmental factors (sharp fall of temperature) and artificially limited feed served as stress factors. It was shown that minks heterozygous for color mutant alleles studied were more resistant to the stressors. This is associated with genetically mediated peculiarities of the action of hypophysial adrenocortical system which is characterized by more adequate reactivity towards stimuli acting. Thus, the effect of heterosis in minks heterozygous for color alleles may well be caused by their increased resistance to stress.     

Optic, olfactory, and vestibular dysmorphogenesis in the homozygous mouse insertional mutant Tg9257

The transgene insertional mutation 9257 on mouse chromosome 18 was originally identified by the circling behavior caused by vestibular abnormalities in heterozygous mutants. To characterize the homozygous phenotype, we generated F2 offspring from the cross (C57BL/6J-tg/+ x DBA/2J). Eye defects ranging in severity from microphthalmia to anophthalmia were observed in the tg/tg offspring. Dysmorphic development of the lens was evident as early as E10.5 in homozygous transgenic mice. Apparent agenesis of the lateral semicircular canal was evident at E14.5. Anomalies of nasomaxillary structures and olfactory neuroepithelium were present in heterozygous and homozygous transgenic mice. The 9257 mutation provides a model for analysis of the morphogenesis of these three neurosensory systems and their associated bony structures.     

Effect of coat color mutations on behavioral polymorphism in farm populations of american minks (Mustela vison Schreber, 1777) and sables (Martes zibellina Linnaeus, 1758)

Behavioral polymorphism estimated by the expression of the defensive reaction towards humans has been studied in farm-bred American minks and sables with different color types. Most animals (both minks and sables) from farm populations displayed passive defensive behavior towards humans in the standard hand catch test. Coat color genes have been found to have pleiotropic effects; they influence both the penetrance and expressivity of domestication behavior: in animals with aberrant color types (both sapphire minks and white-and-black sables), the proportion of animals with domestication behavior and the expressivity of this behavior are significantly higher (p <0.01 and p < 0.001, respectively).     

Allelic inheritance in naturally occurring parthenogenetic offspring of the gonochoric sea star Patiria miniata

Abstract. In laboratory studies of fertilization using the gonochoric broadcast-spawning asterinid sea star Patiria miniata , we found many cases in which some mature eggs spawned by females formed cleavage-stage embryos and feeding bipinnaria larvae without fertilization by sperm. Segregation of maternal microsatellite alleles among the parthenogenetic offspring of known heterozygous females was consistent with several specific modes of asexual reproduction, including polar body suppression. Cryptic outcrossing by sperm contamination was ruled out by the failure to observe non-maternal alleles. The potential for asexual reproduction by the normally outcrossing members of P. miniata may suggest a shared propensity for asexuality among asterinid species from several clades in which isolated adults can produce offspring without outcrossing.     

Timing of births and juvenile mortality in the South American fur seal in Peru

In most species, synchronous, seasonal reproduction is usually associated with higher offspring survival in animals giving birth around the peak, relative to those breeding at the extremes of the reproductive season. In contrast, in the South American fur seal ( Arctocephalus australis ) at Punta San Juan, Peru, females pupping around the peak of births had a greater probability of losing their pups and/or tended to lose them at an earlier age than females breeding early or late in the season. However, the timing of breeding in this population varies little between years and is consistently synchronous. Individual females maintained their relative breeding times in consecutive years, regardless of whether or not they lost their pup the previous year. Thus, pup mortality seems to have no effect on the timing of reproduction in this population.
High breeding densities and the consequent high pup mortality in the S. American fur seal in Peru may have resulted from intense poaching outside protected areas and are of recent origin. The reproductive synchrony in this population could have originally evolved as a response to seasonal variations in food availability and weather conditions, differences in female or pup body condition, predation pressure, sexual selection and/or harassment avoidance, but at the present high density levels has become maladaptive.     

Effect of coat color mutations on behavioral polymorphism in farm populations of American minks (<Emphasis Type="Italic">Mustela vison</Emphasis> Schreber, 1777) and sables (<Emphasis Type="Italic">Martes zibellina</Emphasis> Linnaeus, 1758)

Behavioral polymorphism estimated by the expression of the defensive reaction towards humans has been studied in farm-bred American minks and sables with different color types. Most animals (both minks and sables) from farm populations displayed passive defensive behavior towards humans in the standard hand catch test. Coat color genes have been found to have pleiotropic effects; they influence both the penetrance and expressivity of domestication behavior: in animals with aberrant color types (both sapphire minks and white-and-black sables), the proportion of animals with domestication behavior and the expressivity of this behavior are significantly higher (p < 0.01 and p < 0.001, respectively).     

Effect of mutations affecting coat color on the blood lymphocyte structure in the American mink (Mustela vison Schreber, 1777)

American minks with different genotypes containing the Aleutian coat color allele in the homozygous state, including the single recessive Aleutian (a/a); double recessive sapphire (a/a p/p) and lavender (m/m a/a); triple recessive violet (m/m a/a p/p); and dominant-recessive cross sapphire (S/+ a/a p/p), sapphire leopard (S(K)/+ a/a p/p), and shadow sapphire (S(H)/+ a/a p/p) minks, as well as American minks without the Aleutian allele, including the standard (+/+); single recessive silver-blue (p/p) and hedlund-white (h/h); double recessive pearl (k/k p/p), Finnish topaz (t(S)/t(S) b/b); incompletely dominant royal silver (S(R)/+), standard leopard (S(K)/+), and black crystal (C(R)/+); and dominant-recessive snowy topaz (C(R)/+ t(S)/t(S) b/b) and Kujtezhy-spotted (S(K)/+ b/b) minks have been studied. Homozygosity for the a allele has been found to disturb the subcellular structure of leukocyte, namely the formation of abnormally large granules.     

A mutation affecting the lactate dehydrogenase locus Ldh-1 in the mouse—I. Genetical and electrophoretical characterization

(101/El × C3H/El)F₁ male mice were injected intraperitoneally with the mutagen procarbazine hydrochloride and immediately caged with untreated test-stock females. Crude liver extracts from the offspring were subjected to polyacrylamide gel isoelectric focusing, and the gels were stained for six enzymes. In the experimental group (mutagen treated spermatogonial germ-cell stage), a dominant inherited banding alteration of the lactate dehydrogenase (LDH) pattern was detected. By crossing the heterozygous mutants, homozygotes were obtained that showed much less gel staining intensity. The mutation is codominantly expressed with 100% penetrance. The banding alteration was also observed in muscle, kidney, heart, blood, brain, testis, spleen, and lung. Polyacrylamide gel electrophoresis was performed with all the tissues examined. The mutation causes the intensity of the band corresponding to LDH-A (primary molecular form in muscle) to decrease from that of the wild type, while the intensity of the bands corresponding to LDH-B (primary molecular form in heart) remains constant. It is concluded that the mutation affects the locus coding for LDH of the muscle type. Ldh-1 ^c is proposed as the allele symbol.     

Restoration of reproductive potential after expiration or removal of melengestrol acetate contraceptive implants in Tigers (Panthera tigris)

The need for contraception in the successful management of captive wild animals is becoming increasingly apparent. Because concerns exist regarding the reversibility of the contraceptive implant melengestrol acetate (MGA), reproductive data for 94 female Amur (Panthera tigris altaica) and Sumatran tigers (Panthera tigris sumatrae) were analyzed using survival analyses to evaluate return to reproductive status after implant removal or assumed expiration. Females placed in potential breeding situations after MGA implants were surgically removed showed a 62% return to reproduction by 5.25 years, whereas females with implants that were assumed to have expired showed only a 30% return to reproduction by 6 years. Implanted females did not reproduce as successfully as non‐implanted control females, which showed an 85% probability of reproducing after placement in a new breeding situation by 2.66 years. Parturition increased the probability of reproducing in non‐implanted females, but not in implanted females. Litter size, stillbirths, and offspring survival were not significantly different between non‐implanted, implant‐removed and implant‐expired female tigers. Ten female tigers reproduced both before and after implant placement, and the differences in litter size, stillbirths, and offspring survival were not significant, nor were they significantly different from non‐implanted females. Prior parturition, age when implant was removed, and duration of implantation did not affect the probability of reproducing for females after implant removal. These results show substantial reversibility of MGA implants, leading to 62% successful reproduction after implant removal. The reasons for lower successful reproduction in animals previously treated with the contraceptive compared to non‐implanted females are not known, but a greater delay in reversibility was seen when implants were left in place and only presumed expired. Zoo Biol 26:275–288, 2007. © 2007 Wiley‐Liss, Inc.     

Isolation and Characterization of Sex-Linked Female-Sterile Mutants in DROSOPHILA MELANOGASTER

The purpose of the experiments described was to identify X chromosome genes functioning mainly or exclusively during oogenesis. Two mutagenesis experiments were carried out with ethyl methane sulfonate. Following treatment inducing 60% lethals, 9% of the treated X chromosomes carried a female sterility mutation which did not otherwise seriously affect viability. Among —95 isolated mutants, 19 were heat-sensitive and 5 cold-sensitive. The mutants have been classified as follows: I (16 mutants; 12 complementation groups): the females laid few or no eggs; the defect concerned either ovulation or oogenesis. II (37 mutants; 18 complementation groups): the female laid morphologically abnormal eggs, often with increased membrane permeability. III A (13 mutants; at least 8 complementation groups): the homozygous females were sterile if mated to mutant males; their progeny (homo- and hemizygous) died at a late embryonic stage (11 mutants), at the larval stage (1 mutant) or at the pupal stage (1 mutant). However fertility was partly restored by breeding to wild-type males as shown by survival of some heterozygous descendants. III B (29 mutants; 22 complementation groups): the fertility of the females was not restored by breeding to a wild-type male. Most of the eggs of 13 of the mutants died at a late stage of embryogenesis. The eggs of the others ceased development earlier or, perhaps, remained unfertilized. The distribution of the number of mutants per complementation group led to an estimation of a total of about 150 X-linked genes involved in female fertility. The females of three mutants, heat-sensitive and totally sterile at 29°, produced at a lower temperature descendants morphologically abnormal or deprived of germ cells. Three other mutants not described in detail showed a reduction in female fertility with many descendants lacking germ cells. A desirable mutant which was not recovered was one with normal fertile females producing descendants which, regardless of their genotype, bore specific morphological abnormalities. The value of the mutants isolated for analysis of the complex processes leading to egg formation and initiation of development is discussed.     

Energetics of age-specific reproductive effort in female Harp seals, Phoca groenlandica

The theory of reproductive effort is commonly viewed in the perspective of the cost of offspring to the parent. This interpretation predicts that older females make a greater reproductive effort than younger females, for whom the cost of lost future offspring is less. The benefit early-born offspring represent in future generations is greater than that of late-born offspring in most natural populations, so, alternatively, young females should make a greater reproductive effort. These hypotheses were investigated in nursing Harp seals by examining age-specific reproductive effort in terms of energetic maternal investment.
Younger Harp seal females lost weight at the same rate as did older females. Moreover. since younger, growing females tended to start lactation with less blubber than older females. weight loss during 10 days (d) of lactation represented a greater proportion of stored energy for young females. A successfully weaned pup, therefore, constituted a greater reproductive effort for them than for older females, consistent with benefit–oriented predictions from theory.
A model is presented to outline the components of an annual energy budget for female Harp seals in the context of reproductive effort. This model indicates that young females may devote a greater proportion of their annual net energy to reproduction and take a greater risk of lost future reproduction. It also identifies areas of inadequacy of existing data on pinniped energy budgets.     

Studies on prenatal and postnatal development in rats exposed to 60-Hz electric fields

A series of three experiments was performed to determine the effects of 30-day exposures to uniform 60-Hz electric fields (100 kV/m) on reproduction and on growth and development in the fetuses and offspring of rats. In the first experiment, exposure of females for 6 days prior to and during the mating period did not affect their reproductive performance, and continued exposure through 20 days of gestation (dg) did not affect the viability, size, or morphology of their fetuses. In the second experiment, exposure of the pregnant rat was begun on 0 dg and continued until the resulting offspring reached 8 days of age. In the third experiment, exposure began at 17 dg and continued through 25 days of postnatal life. In the second and third experiments, no statistically significant differences suggesting impairment of the growth or survival of exposed offspring were detected. In the second experiment, a significantly greater percentage of the exposed offspring showed movement, standing, and grooming at 14 days of age than among-sham-exposed offspring. There was a significant decrease at 14 days in the percentage of exposed offspring displaying the righting reflex in the second experiment and negative geotropism in the third experiment. These differences were all transient and were not found when the animals were tested again at 21 days of age. Evaluation of the reproductive integrity of the offspring of the second experiment did not disclose any deficits.     

Dominant cataract and recessive specific locus mutations in offspring of X-irradiated male mice

Male mice were X-irradiated with 3.0 + 3.0 Gy or 5.1 + 5.1 Gy (fractionation interval 24 h). The offspring were screened for dominant cataract and recessive specific locus mutations. In the 3.0 + 3.0-Gy spermatogonial treatment group, 3 dominant cataract mutations were confirmed in 15 551 offspring examined and 29 specific locus mutations were recovered in 18 139 offspring. In the post-spermatogonial treatment group, 1 dominant cataract mutation was obtained in 1120 offspring and 1 recessive specific locus mutation was recovered in 1127 offspring. The induced mutation rate per locus, per gamete, per Gy calculated for recessive specific locus mutations is 2.0 X 10(-5) in post-spermatogonial stages and 3.7 X 10(-5) in spermatogonia. For dominant cataract mutations, assuming 30 loci, the induced mutation rate is 5.0 X 10(-6) in the post-spermatogonial stages and 1.1 X 10(-6) in spermatogonia. In the 5.1 + 5.1-Gy spermatogonial treatment group, 3 dominant cataract mutations were obtained in 11 205 offspring, whereas in 13 201 offspring 27 recessive specific locus mutations were detected in the spermatogonial group. In the post-spermatogonial treatment group no dominant cataract mutation was observed in 425 offspring and 2 recessive specific locus mutations were detected in 445 offspring. The induced mutation rate per locus, gamete and Gy in spermatogonia for recessive specific locus mutations is 2.8 X 10(-5) and for dominant cataract mutations 0.9 X 10(-6). In post-spermatogonial stages, the mutation rate for recessive specific locus alleles is 6.2 X 10(-5). In the concurrent untreated control group, in 11 036 offspring no dominant cataract mutation and in 23 518 offspring no recessive specific locus mutation was observed. Litter size and the number of carriers at weaning have been determined in the confirmation crosses of the obtained dominant cataract mutants as indicators of viability and penetrance effects. Two mutants had a statistically significantly reduced litter size and one mutant had a statistically significantly reduced penetrance.     

Host selection by virgin and inseminated females of the parasitic wasp, Dinarmus basalis (Pteromalidae, Hymenoptera)

1. Fitness is related to reproduction and survival. There apparently exists a negative correlation between the numbers of male and female offspring. There also exists a trade-off between survival and reproduction. This paper investigates optimal decisions with the reproduction and survival trade-off in host selection by wasps.
2. Whereas inseminated female wasps could manipulate the sex of their offspring, virgin females produced only male offspring. I surveyed behavioural differences and the consequences of oviposition by inseminated and virgin females of a solitary parasitic wasp in host choice situations.
3. Two host types were available at the same time to both inseminated and virgin female wasps: one (a 17-day-old host in one bean) presenting difficulties for the laying of eggs, but more benefits for the offspring and the other (five 12- or 13-day-old hosts in one bean) easier for the female wasp for laying of eggs but less beneficial for the offspring.
4. Inseminated female wasps chose more 17-day-old hosts than 12-day-old hosts, but more 13-day-old hosts than 17-day-old hosts in each pair-wise choice. Virgin females chose the smaller hosts in both situations.
5. Virgin females, having greater longevity than inseminated females, laid larger numbers of eggs than the inseminated females during their lifetime by adopting an energy-saving host choice that had little effect on male offspring fitness.