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We studied facultative dominant lethal mutations obtained earlier in Drosophila melanogaster. In some genotypes, these mutations were expressed as lethals, but in other genotypes they lacked this expression. The mutations were maintained in the following cultures: (1) females Muller-5 heterozygous for the mutation; (2) males crossed to attached-X females; and females and males homozygous for the mutation. During culturing, many mutations were found to give rise to phenotypically abnormal progeny. Generally, these abnormalities were morphoses involving various body parts; they were mostly asymmetric and non-heritable. Maternal and paternal effects in the formation of morphoses were observed. In four cases, dimorphic mutations were recorded: a female homozygous for the mutation had mutant phenotype whereas its male counterpart was phenotypically normal. The mutations were recessive with regard to the norm. New phenotypes behaving as mutations with incomplete penetrance arose during culturing. In cultures of mutant homozygotes phenocopies would appear en masse; they would persist for one or two generations and disappear. One wave of phenocopies succeeded another. Visible phenotypes appeared, which further behaved as ordinary recessive mutations. We concluded that these visible manifestations are characteristic for regulatory mutations controlling ontogeny. Their appearance is explained by the activation of new regulatory scenarios caused by blocking standard regulatory pathways. 相似文献
2.
B. F. Chadov E. V. Chadova S. A. Kopyl E. A. Khotskina N. B. Fedorova 《Russian Journal of Genetics》2004,40(3):271-281
We studied facultative dominant lethal mutations obtained earlier inDrosophila melanogaster. In some genotypes, these mutations were expressed as lethals, but in other genotypes they lacked this expression. The mutations were maintained in the following cultures: (1) females Muller-5 heterozygous for the mutation; (2) males crossed to attached-Xfemales; and (3) females and males homozygous for the mutation. During culturing, many mutations were found to give rise to phenotypically abnormal progeny. Generally, these abnormalities were morphoses involving various body parts; they were mostly asymmetric and nonheritable. Maternal and paternal effects in the formation of morphoses were observed. In four cases, dimorphic mutations were recorded: a female homozygous for the mutation had mutant phenotype whereas its male counterpart was phenotypically normal. The mutations were recessive with regard to the norm. New phenotypes behaving as mutations with incomplete penetrance arose during culturing. In cultures of mutant homozygotes phenocopies would appear en masse; they would persist for one or two generations and disappear. One wave of phenocopies succeeded another. Visible phenotypes appeared, which further behaved as ordinary recessive mutations. We concluded that these visible manifestations are characteristic for regulatory mutations controlling ontogeny. Their appearance is explained by the activation of new regulatory scenarios caused by blocking standard regulatory pathways. 相似文献
3.
B. F. Chadov E. V. Chadova E. A. Khotskina N. B. Federova 《Russian Journal of Genetics》2009,45(3):276-286
The phenomenology of genomic destabilization is described in Drosophila melanogaster mutants containing radiation-induced conditional dominant lethals in the X chromosome and in autosome 2. Destabilization manifests itself as (1) the loss or decrease of lethality of previously lethal mutations; (2) the loss of expression of visible dominant mutations in an opposite homolog; (3) chromosomal instability resulting in the loss of the X chromosome in germline and somatic cells; (4) the occurrence of novel mutations (secondary mutagenesis); (5) the occurrence of single and mass modifications; (6) disturbances in individual development (formation of morphoses). The key event for the shift of the genome from the stable state into the unstable one is the occurrence of a conditional dominant lethal mutation. 相似文献
4.
Spontaneous formation of half-translocations (HTs) of X · 2L and Y · 2L types in
females were studied. The HTs were the result of interchange between the
and C(2L) autosomal compound in their precentromeric heterochromatic regions. The HTs produced in previous experiments with
females were also analysed.The great majority of spontaneous interchanges were of meiotic origin. Of 13 HT offspring yielded by
females, 10 were X-cross-overs. 8 HT individuals among the offspring of
females were X-crossovers. Based on the segregation pattern of chromosomes following interchange, it is concluded that interchange takes place during meiotic prophase. Interchange and crossing over are concomitant events giving rise to the
trivalent. In this trivalent, the euchromatic region of
compound pairs with the X euchromatic region, and the
heterochromatic region with the C(2L). The heterochromatic regions of the X and
in the trivalent are asynaptic. Two lines of evidence for this partial asynapsis were obtained: (1) the high rate of
non-disjunction (34.1% in HT offspring of
females); (2) the regular segregation of the X chromosome with C(2R). The crossing over in the X-euchromatic region, which was associated with
interchange, was disturbed (a high proportion of multiple exchanges). Crossing-over disturbance and the high level of non-disjunction in the HT offspring were not caused by the presence of the
and autosomal compounds in the stock investigated.It is concluded that the spontaneous asynapsis of the X and
regions initiates
pairing and interchange, thereby giving rise to abnormal
crossing over and disjunction. Partial asynapsis of homologues as the sufficient cause for non-disjunction and non-homologue pairing is discussed. 相似文献
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5.
Chadov BF Fedorova NB Chadova EV Khotskina EA Moshkin MP Petrovskiĭ DV 《Genetika》2010,46(9):1196-1201
Conditional dominant lethals (CDL) represent a special class of genetic mutations observed in Drosophila. Mutation manifests as a dominant allele in one genotype, but lethality is not expressed in another genotype. CDL mutants exhibit a set of traits discriminating them from classic mutations. We observed unusually high mobility of flies and high sexual activity of males carrying these mutations. We used special tests for evaluation of energy metabolism of CDL mutants. Indirect calorimetry (CO2 excretion measurement) has been used for estimation of energy exchange in four mutant and two control fly lines. A Special device has been used for evaluation of locomotor activity of these fly lines. Energy exchange and locomotor activity in CDL mutants were significantly higher than in control lines. We conclude that some genetic mutations are capable of increasing energy dissipation in their carriers. 相似文献
6.
B. F. Chadov E. V. Chadova S. A. Kopyl E. V. Artemova E. A. Khotskina N. B. Fedorova 《Russian Journal of Genetics》2004,40(9):945-958
Based on the Mendelian approach to heredity, modern genetics describes inheritance of characters belonging to the category of intraspecific difference. the other large category of characters,intraspecific similarity, stays out of investigation. In this review, the genome part responsible for intraspecific similarity is considered as invariant and regulatory. An approach to studying the invariant part of the Drosophila melanogaster genome is formulated and the results of examining this genome part are presented. The expression of mutations at genes in the invariant genome part is different from that of Mendelian genes. We conclude that these genes are present in the genome in multiple copies and they are functionally haploid in the diploid genome. Severe abnormalities of development appearing in the progeny of mutant parents suggest that the mutant genes are genes regulating ontogeny. A hypothesis on an elementary ontogenetic event is advanced and the general scheme of ontogeny is presented. A concept on two types of gene allelism (cis- and trans-allelism) is formulated. This approach opens a possibility for studying genetic material responsible for the formation of intraspecific similarity characters at different taxonomic levels on the basis of crossing individuals of the same species. 相似文献
7.
Chadov B. F. Chadova E. V. Khotskina E. A. Artemova E. V. Fedorova N. B. 《Russian Journal of Genetics》2004,40(7):723-731
Effect of chromosomal rearrangements on the expression of mutations was studied in Drosophila melanogaster regulatory genes. These were facultative dominant lethals and recessive lethals on the X chromosome obtained by the classical Muller-5 method. Chromosomal rearrangements drastically changed the expression of regulatory gene mutations. Rearrangements either caused the lethal effect of mutations or suppressed the already present lethality. The action of rearrangements exhibited the maternal or paternal effect. Irrespective of the presence in the genome of mutations of regulatory genes, a rearrangement acted as a factor decreasing fertility of the organism. The rearrangement effect is identical to the expression of regulatory genes per se. It is concluded that the chromosomal rearrangement affects the examined regulatory genes indirectly through a change in the operation of regulatory genes located within the rearrangement. Thus, rearrangements gain great importance for the definition of the pattern of genome functional activity. Widespread distribution of rearrangements in individual genotypes and their effectivity in the process of speciation are thus explained. 相似文献
8.
Effect of chromosomal rearrangements on the expression of mutations was studied in Drosophila melanogaster regulatory genes. These were facultative dominant lethals and recessive lethals on the X chromosome obtained by the classical Muller-5 method. Chromosomal rearrangements drastically changed the expression of regulatory gene mutations. Rearrangements either caused the lethal effect of mutations or suppressed the already present lethality. The action of rearrangements exhibited the maternal or paternal effect. Irrespective of the presence in the genome of mutations at regulatory genes, a rearrangement acted as a factor decreasing fertility of the organism. The rearrangement effect is identical to the expression of regulatory genes per se. It is concluded that the chromosomal rearrangement affects the examined regulatory genes indirectly through a change in the operation of regulatory genes located within the rearrangement. Thus, rearrangements gain great importance for the definition of the pattern of genome functional activity. Widespread distribution of rearrangements in individual genotypes and their effectivity in the process of speciation are thus explained. 相似文献
9.
Based on the Mendelian approach to heredity, modern genetics describes inheritance of characters belonging to the category of intraspecific difference. The other large category of characters, intraspecific similarity, stays out of investigation. In this review, the genome part responsible for intraspecific similarity is considered as invariant and regulatory. An approach to studying the invariant part of the Drosophila melanogaster genome is formulated and the results of examining this genome part are presented. The expression of mutations at genes in the invariant genome part is different from that of Mendelian genes. We conclude that these genes are present in the genome in multiple copies and they are functionally haploid in the diploid genome. Severe abnormalities of development appearing in the progeny of mutant parents suggest that the mutant genes are genes regulating ontogeny. A hypothesis on an elementary ontogenetic event is advanced and the general scheme of ontogeny is presented. A concept on two types of gene allelism (cis- and trans-allelism) is formulated. This approach opens a possibility for studying genetic material responsible for the formation of intraspecific similarity characters at different taxonomic levels on the basis of crossing individuals of the same species. 相似文献
10.
B. F. Chadov N. B. Fedorova E. V. Chadova E. A. Khotskina M. P. Moshkin D. V. Petrovski 《Russian Journal of Genetics》2010,46(9):1062-1066
Conditional dominant lethals (CDL) represent a special class of genetic mutations observed in Drosophila. Mutation manifests as a dominant lethal in one genotype, but lethality is not expressed in another genotype. CDL mutants
exhibit a set of traits discriminating them from classic mutations. We observed unusually high mobility of flies and high
sexual activity of males carrying these mutations. We used special tests for evaluation of energy metabolism of CDL mutants.
Indirect calorimetry (CO2 excretion measurement) has been used for estimation of energy exchange in four mutant and two control fly lines. A special
device has been used for evaluation of locomotor activity of these fly lines. Energy exchange and locomotor activity in CDL
mutants were significantly higher than in control lines. We conclude that some genetic mutations are capable of increasing
energy dissipation in their carriers. 相似文献
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