Role of recessive lethal genes in spontaneous embryonic mortality in noninbred mouse and rat populations in Cuba

1983 ◽  
Vol 95 (3) ◽  
pp. 339-341 ◽  
Author(s):  
Kh. Kh. Semenov ◽  
D. Walker
Keyword(s):  
Embryonic Mortality ◽  
Recessive Lethal ◽  
Lethal Genes

The role of the genome in the development of the haploid syndrome in Anura

Development ◽  
1966 ◽  
Vol 16 (3) ◽  
pp. 559-568
Author(s):  
Louie Hamilton
Keyword(s):  
Good Evidence ◽  
Contributory Factor ◽  
Diploid Nucleus ◽  
Haploid Nucleus ◽  
Recessive Lethal ◽  
Partial Failure ◽  
Lethal Genes

The problem of the factors involved in the development of the haploid syndrome in anuran embryos is as yet unsolved. It is known that about 90 % of all haploid frog embryos develop the haploid syndrome, which is characterized by the presence of oedema and sluggishness, by reduction in pigmentation and in the efficiency of the heart and circulation, and by a partial failure of the gut to coil and of muscle to differentiate. The two most favoured explanations of the development of the haploid syndrome have been nucleocytoplasmic imbalance, since a haploid nucleus is only half the size of a diploid nucleus in the same-sized egg, and unmasked recessive lethal genes. There is good evidence that an abnormal nucleocytoplasmic ratio is an important contributory factor in the development of the haploid syndrome. Briggs (1949) compared populations of haploids developing from large and small eggs and Subtelny (1958) compared the development of haploids and homozygous diploids which possessed a reduplicated set of haploid chromosomes.

scholarly journals Protective role of methanol extracts of Gentiana asclepiadea L. and G. cruciata L. against genotoxic damage induced by ethyl methanesulfonate

Genetika ◽  
2013 ◽  
Vol 45 (2) ◽  
pp. 329-340 ◽  
Author(s):  
Sanja Matic ◽  
Snezana Stanic ◽  
Slavica Solujic ◽  
Nevena Stankovic ◽  
Milan Mladenovic ◽  
...  
Keyword(s):  
Aerial Part ◽  
Protective Role ◽  
Negative Control ◽  
Ethyl Methanesulfonate ◽  
Recessive Lethal ◽  
Methanol Extracts ◽  
Strong Mutagen ◽  
Gentiana Cruciata

The methanol extracts from the underground and aerial part of the two species of Gentiana genus, Gentiana asclepiadea L. and Gentiana cruciata L. from Serbia, were investigated for their antigenotoxic activity against wellestablished mutagenic agent ethyl methanesulfonate (EMS) using the in vivo sexlinked recessive lethal (SLRL) test on Drosophila melanogaster. For this purpose, three days old Canton S males were treated with the potent mutagen EMS in concentration of 0.75 ppm, alone and combined with methanol extracts obtained from underground or aerial part of G. asclepiadea and G. cruciata in concentration of 5%, separately. Although EMS in concentration of 0.75 ppm increased the mutation frequency in all three broods, post-treatments with methanol extracts obtained from the underground and aerial part of G. asclepiadea and G. cruciata in concentration of 5%, respectively, drastically reduced the frequency of sex-linked recessive lethal mutations induced by EMS. Compared to the sucrose, as a negative control, methanol extract obtained from underground part of G. cruciata showed the most potent antigenotoxic activity. Extracts from the underground and aerial part of the two species of Gentiana genus, G. asclepiadea L. and G. cruciata L. from Serbia used in our experiments showed a clear antimutagenic effect, reducing the frequency of mutations induced by a strong mutagen such as EMS.

Biosystematic studies in the Stylidium crassifolium species complex (Stylidiaceae)

1979 ◽  
Vol 27 (1) ◽  
pp. 27 ◽  
Author(s):  
BJ Banyard ◽  
SH James
Keyword(s):  
Species Complex ◽  
Genetic System ◽  
Lethal Gene ◽  
Great Efficiency ◽  
Intermediate Species ◽  
Gene Arrays ◽  
Recessive Lethal ◽  
Tetraploid Form ◽  
Diploid Populations ◽  
Lethal Genes

Stylidium elongatum Benth. (n = 13, 26) and Stylidium crassifolium R. Br. (n = 14, 28) have been restored to specific status and a morphologically intermediate species, Stylidium confluens sp. nov. (n = 14), is described. Polyploid entities in the complex have not been given taxonomic ranks although the tetraploid form of elongatum may be considered worthy of subspecific rank, as it is ecologically distinct and contiguously allopatric to its progenitor and to confluens, forming a buffer between these two diploid entities. Tetraploid populations in crassifolium occur within the distributional range of the diploid. All three species carry recessive lethal gene arrays which eliminate the products of self-pollination with great efficiency and result in crosses between close populations yielding seed more effectively than crosses within populations. There is evidence that interpopulational coadaptation may break down with increasing distance between populations. Polyploidy in crassifolium is probably a conservative response in the genetic system of a species where concentrations of lethal genes in small diploid populations became disadvantageous.

scholarly journals Analysis of embryonic mortality frequency in Drosophila melanogaster stocks with radius incompletus mutation under inbreeding conditions

2018 ◽  
Keyword(s):  
Drosophila Melanogaster ◽  
Embryonic Mortality ◽  
Total Frequency ◽  
Lethal Mutations ◽  
Dominant Lethal ◽  
Dominant Lethal Mutations ◽  
External Conditions ◽  
High Level ◽  
Selection Of

It is known that inbreeding leads to homozygotization of alleles of the most genes. The rate of this process is determined by the degree of kinship between crossed individuals. In addition, inbred breeding is accompanied by a change in the structure and functioning of the genome of cells of females’ generative system: mutational level increases and oogenetic segregation may be violated. This leads to a decrease in the number of laid eggs and an increase in the level of embryonic mortality. This process, described as "the effect of resistance to selection," is aimed at adapting to external conditions and associated with the selection of viable offspring. The character of manifestations of mutational variability is determined to a large extent by the direction of selection. However, up to now our knowledge of the role of the genotype in controlling the level of embryonic mortality in Drosophila melanogaster stocks in conditions of inbred breeding is not deep enough. The purpose of our work was to analyze the frequency of dominant lethal mutations in Drosophila stocks from radiation-contaminated regions of Ukraine (Polesskoe and Ozero), carrying radius incompletus mutation, depending on the degree of inbreeding. It is shown that under conditions of severe inbreeding (without selection) changes in the total frequency of dominant lethal mutations have a cyclic character, which depends on the genotype of the stocks. So, in radius incompletus stock, the indicator studied increases after 10 generations of selection and remains at enough high level for 20 generations. For the stocks from radiation-contaminated territories of Ukraine with radius incompletus mutation, which are contrasting in the level of embryonic mortality, two decrease peaks are shown (for the stock ri(Oz) – after 5 and 65 generations of inbreeding) and an increase (for the line ri(Pol) – after 5 and 32 generations of inbreeding) of the total frequency of dominant lethal mutations. The main factor influencing the change in the mortality level at the stage of early embryogenesis in Drosophila carrying radius incompletus mutation is the genotype of the stocks that are used in the work. It’s contribution increases after 10 (h2gen=44.78), 15 (h2gen=45.86) and 100 (h2gen=46.36) generations of inbreeding. The effect of inbred breeding was observed after 32 (h2inbr=22.61) and 65 (h2inbr=11.89) generations. The combined effect of both factors on the total frequency of dominant lethal mutations is shown for each of the generations studied. The highest values were shown after the 5th (h2comb=53.86) and the 65th (h2comb =40.63) generations of inbred breeding.

scholarly journals Colonization of the Americas by Drosophila subobscura: lethal-gene allelism and association with chromosomal arrangements.

Genetics ◽  
1995 ◽  
Vol 140 (4) ◽  
pp. 1297-1305
Author(s):  
F Mestres ◽  
L Serra ◽  
F J Ayala
Keyword(s):  
Drosophila Subobscura ◽  
Rapid Expansion ◽  
Lethal Gene ◽  
Latitudinal Cline ◽  
Recessive Lethal ◽  
Central California ◽  
High Incidence ◽  
Palearctic Species ◽  
Lethal Allelism ◽  
Lethal Genes

Abstract Drosophila subobscura is a Palearctic species that has recently colonized the Americas. It was first found in 1978 in Puerto Montt, Chile, and in 1982 in Port Townsend, WA. The colonization and rapid expansion of the species in western South and North America provides distinctive opportunities for investigating the process of evolution in action. The inversion polymorphism in the O chromosome from populations of central California and northern Washington, separated by 1300 km, corresponds to a previously observed latitudinal cline, also observed in Europe. Recessive lethal genes are not randomly distributed among the chromosomal arrangements. The incidence of lethal allelism is high, yielding unrealistically low estimates of the effective size of these populations (on the order of 1000 individuals). The high incidence of lethal allelism is likely to be a consequence of the low number of the American colonizers (on the order of 10-100 individuals), but the persistence of the allelism over several years suggests that some lethal-carrying chromosomes may be heterotic owing to shared associations between lethal and other genes.

scholarly journals Mosaic CRISPR-stop enables rapid phenotyping of nonsense mutations in essential genes

Development ◽  
2021 ◽  
Vol 148 (5) ◽  
pp. dev196899
Author(s):  
Guangqin Wang ◽  
Chao Li ◽  
Shunji He ◽  
Zhiyong Liu
Keyword(s):  
Outer Hair Cells ◽  
Conditional Knockout ◽  
Rapid Screening ◽  
Lethal Gene ◽  
Loss Of Function ◽  
Cell Stage ◽  
Nonsense Mutations ◽  
Protein Coding ◽  
Lethal Genes

ABSTRACTCRISPR-stop converts protein-coding sequences into stop codons, which, in the appropriate location, results in a null allele. CRISPR-stop induction in one-cell-stage zygotes generates Founder 0 (F0) mice that are homozygous mutants; this avoids mouse breeding and serves as a rapid screening approach for nonlethal genes. However, loss of function of 25% of mammalian genes causes early lethality. Here, we induced CRISPR-stop in one of the two blastomeres of the zygote, a method we name mosaic CRISPR-stop, to produce mosaic Atoh1 and Sox10 F0 mice; these mice not only survived longer than regular Atoh1/Sox10 knockout mice but also displayed their recognized cochlear phenotypes. Moreover, by using mosaic CRISPR-stop, we uncovered a previously unknown role of another lethal gene, Rbm24, in the survival of cochlear outer hair cells (OHCs), and we further validated the importance of Rbm24 in OHCs by using our Rbm24 conditional knockout model. Together, our results demonstrated that mosaic CRISPR-stop is reliable and rapid, and we believe this method will facilitate rapid genetic screening of developmentally lethal genes in the mouse inner ear and also in other organs.

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