Segregation analysis of the testis-determining autosomal trait, Tda, that differs between the C57BL/6J and DBA/2J mouse strains suggests a multigenic threshold model

Genome ◽  
1996 ◽  
Vol 39 (2) ◽  
pp. 322-335 ◽  
Author(s):  
James R. Eisner ◽  
Brenda A. Eales ◽  
Fred G. Biddle
Keyword(s):  
Y Chromosome ◽  
Segregation Analysis ◽  
Threshold Model ◽  
Single Gene ◽  
Mouse Strains ◽  
Gene Model ◽  
Backcross Generation ◽  
Testis Development ◽  
Consomic Strain ◽  
Strain Background

The testis-determining autosomal trait (Tda) of the mouse was uncovered when the Y chromosome of the poschiavinus variety of Mus musculus domesticus was introduced into the C57BL/6J laboratory strain background. Testis development is normal in the F1 generation but, in the backcross and subsequent crosses to C57BL/6J females, XY individuals with the poschiavinus Y chromosome expressed bilateral ovaries or various combinations of an ovotestis with a contralateral ovary or testis or bilateral ovotestes and few had testes bilaterally. In other strain backgrounds, such as DBA/2J, XY individuals with the poschiavinus Y chromosome always expressed normal testes bilaterally. The first breeding analysis of this difference in the interaction of strain background with the poschiavinus Y chromosome suggested that the Tda trait was due to a single gene, but attempts to map it failed. We constructed two strains of C57BL/6J and DBA/2J that are consomic for the poschiavinus Y chromosome in order to conduct a segregation analysis of the Tda trait. In the C57BL/6J.Y-POS consomic strain, liability to express incomplete testis development is normally distributed and thresholds in development specify the probability of different classes of ovary, ovotestis, and testis combinations. Testis development is complete in the DBA/2J.Y-POS consomic strain. We demonstrated previously that the Tda trait of C57BL/6J is recessive to that of DBA/2J and the segregating first backcross generation of embryos rejected the single-gene model. We have extended our analysis to a F2 generation of embryos that also rejects a single-gene model. We also report a test mating analysis of the first backcross generation. It was initiated to provide an independent assessment of the single-gene model, but the analysis of the distribution of test mating results suggests that the difference in the Tda trait between C57BL/6J and DBA/2J may be due to a small number of loci, possibly four or five, and that the phenotypic effect between loci may be additive. Key words : mouse, Y chromosome, gonadal hermaphrodites, primary sex determination, autosomal testis-determining genes, multigenic threshold model.

scholarly journals Mapping QTL for Day-neutrality in Strawberry

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 786B-786
Author(s):  
Cholani K. Weebadde* ◽  
James F. Hancock
Keyword(s):  
Gene Expression ◽  
Molecular Markers ◽  
Linkage Mapping ◽  
Threshold Model ◽  
Single Gene ◽  
Small Population ◽  
Linkage Groups ◽  
Qtl Detection ◽  
Gene Model ◽  
Mapping Approach

While it is important for strawberry breeders to know the genetics of day-neutrality, evidence for inheritance of the trait is still contradictory. It is not known how many genes govern the trait, to what extent each gene affects phenotype and how the environment influences gene expression. Several recent studies point toward a polygenic threshold model and a rejection of the single gene model. A linkage mapping approach is being used to determine if day neutrality can be mapped to several different quantitative trait loci (QTL) that may represent different genes. To confirm that a linkage mapping approach is the method of choice for QTL detection, a small population of the cross `Honeoye' x `Tribute' consisting of 57 progeny segregating for the trait was genotyped with single dose restriction fragment (SDRF) markers and a preliminary genetic map was created using Join Map 3.0. Results separated the molecular markers into at least 24 linkage groups and several putative QTL for day neutrality were identified indicating that the technique will be successful. However, due to the complexity of the octoploid genome of strawberry, over 200 progeny need to be genotyped to build a complete map that includes the 56 linkage groups of the genome. Furthermore, for determining QTL, an accurate phenotypic evaluation is critical. Individuals of the population above were phenotyped under field conditions (East Lansing, Mich.) in 2002 and 2003, and are now being analyzed under controlled temperature and photoperiod conditions for confirmation of the QTL detected for the trait. A larger population of the same cross with over 200 progeny has also been generated and will be mapped using molecular markers after determining their phenotype under the same environmental conditions.

The testis-determining autosomal trait, Tda-1, of C57BL/6J is determined by more than a single autosomal gene when compared with DBA/2J mice

Genome ◽  
1994 ◽  
Vol 37 (2) ◽  
pp. 296-304 ◽  
Author(s):  
Fred G. Biddle ◽  
James R. Eisner ◽  
Brenda A. Eales
Keyword(s):  
Y Chromosome ◽  
Congenic Strain ◽  
Autosomal Recessive ◽  
Recombinant Inbred Strain ◽  
Single Gene ◽  
Autosomal Gene ◽  
Mus Musculus Domesticus ◽  
Homozygous State ◽  
Recessive Factor ◽  
Testis Development

The putative Tda-1 or testis-determining autosomal trait of the C57BL/6J mouse strain came to attention when the Y chromosome from the poschiavinus variety of Mus musculus domesticus was introduced into C57BL/6J by backcross matings. The F1 generation expressed normal testis development in XY individuals with the poschiavinus Y chromosome. In the backcross and subsequent crosses to C57BL/6J females, XY individuals expressed ovaries bilaterally or various combinations of an ovotestis with a contralateral ovary or testis or bilateral ovotestes and a few had testes bilaterally. Some of the previous breeding data appeared to support the hypothesis that C57BL/6J had an autosomal recessive factor that differed from the poschiavinus strain and, in the homozygous state, caused incomplete testis development with the poschiavinus Y chromosome. Subsequent attempts to map the Tda-1 factor, using a recombinant inbred strain approach, failed to localize Tda-1 and this suggests it might map to different chromosomes depending on which strain pairs are used. We constructed two strains of C57BL/6J and DBA/2J that are congenic for the poschiavinus Y chromsome. In the C57BL/6J.Y-POS congenic strain, liability to express incomplete testis development is normally distributed and thresholds in development specify the probability (or areas under the normal distribution) of different classes of ovary, ovotestis, and testis combinations. Testis development is normal in the DBA/2J.Y-POS congenic strain. With the two congenic strains and their normal parental strains we were able to conduct standard crosses to examine the reciprocal F1 and four types of backcross generations to the C57BL/6J strain in which all XY individuals have the poschiavinus Y chromosome. The Tda-1 trait of C57BL/6J is recessive to DBA/2J, but the segregating backcross generations reject the single gene model.Key words: mouse, Y chromosome, gonadal hermaphrodites, primary sex determination.

Inheritance of anthracnose resistance in the tropical pasture legume Stylosanthes hamata

1995 ◽  
Vol 46 (7) ◽  
pp. 1353 ◽  
Author(s):  
N Iamsupasit ◽  
DF Cameron ◽  
M Cooper ◽  
S Chakraborty ◽  
LA Edye
Keyword(s):  
Combining Ability ◽  
Colletotrichum Gloeosporioides ◽  
Single Gene ◽  
General Combining Ability ◽  
Tropical Pasture ◽  
Gene Model ◽  
Stylosanthes Hamata ◽  
Moderately Resistant ◽  
Half Diallel ◽  
Pasture Legume

Eight tetraploid accessions of the tropical pasture legume Stylosanthes hamata with varying levels of response to the anthracnose pathogen (Colletotrichum gloeosporioides) were crossed in a half diallel scheme. Based on mean disease severity ratings (MDR), two parents, 55830 and 75164, were grouped as resistant (R), 55828 and 65365 were susceptible (S), and the remaining four, cvv. Verano and Amiga and 65371 and 75162 were moderately resistant (MR). Of these, the two resistant parents appear to carry different genes for resistance. The MDR of 20 of the 28 F2 populations was significantly different from their mid-parent MDR and the expression of resistance, in most cases, was recessive. Only a limited number of the F2 distributions for crosses between RxS, RxMR and MRxS parents conformed to a single gene model. The inheritance patterns observed were considered to be predominantly quantitative. Variation for general combining ability, was as large as or larger than that for specific combining ability suggesting that a large proportion of the genetic differences among the parents was additive. The finding that the resistance is inherited as a quantitative trait is consistent with results on the epidemiology of anthracnose in tetraploid S. hamata.

Inheritance of a schizophrenia-like deficit in auditory gating fits a one gene model in inbred mouse strains

1997 ◽  
Vol 24 (1-2) ◽  
pp. 60
Author(s):  
Karen E. Stevens ◽  
Allan C. Collins ◽  
Michael J. Marks ◽  
Jerry A. Stitzel ◽  
Robert Freedman
Keyword(s):  
Inbred Mouse ◽  
Mouse Strains ◽  
Inbred Mouse Strains ◽  
Gene Model ◽  
Auditory Gating

scholarly journals Two-gene Interaction and Linkage for Bitterfree Foliage in Cucumber

1998 ◽  
Vol 123 (3) ◽  
pp. 401-403 ◽  
Author(s):  
Todd C. Wehner ◽  
J.S. Liu ◽  
Jack E. Staub
Keyword(s):  
Cucumis Sativus ◽  
Single Gene ◽  
Gene Interaction ◽  
Inbred Lines ◽  
Gene Model ◽  
Gene Map ◽  
Map Distance

A second gene for bitterfree foliage in cucumber (Cucumis sativus L.) was discovered. In a cross between two inbred lines having bitterfree foliage (NCG-093 and WI2757), the F1 progeny were bitter, the F2 progeny segregation frequency fit a ratio of 9 bitter : 7 bitterfree, and the BC1 segregation frequencies fit a ratio of 1 bitter : 1 bitterfree. Thus, a second factor nonallelic to the previous bitterfree gene, bi, controls the bitterfree trait. When F2 and BC1 progeny resulting from crosses of bitterfree NCG-093 with other bitter lines were studied, the second factor for bitterfree in NCG-093 fit a recessive, single-gene model. The existence of a second, recessive bitterfree gene was confirmed in additional crosses, and the gene was designated bi-2. Further analysis of two crosses indicated that bi-2 was linked with the short petiole (sp) gene (map distance = 11 cM).

Human SRY expression at the sex-determining period is insufficient to drive testis development in mice

Endocrinology ◽  
2021 ◽  
Author(s):  
Atsumi Tsuji-Hosokawa ◽  
Yuya Ogawa ◽  
Iku Tsuchiya ◽  
Miho Terao ◽  
Shuji Takada
Keyword(s):  
Mouse Model ◽  
Y Chromosome ◽  
Initiation Factor ◽  
Reading Frame ◽  
Testis Development ◽  
Significant Difference ◽  
Exon 1 ◽  
The Difference ◽  
Cortical Regions ◽  
Species Specific

Abstract The sex-determining region of the Y chromosome, Sry/SRY, is an initiation factor for testis development in both humans and mice. Although the functional compatibility between murine SRY and human SRY was previously examined in transgenic mice, their equivalency remains inconclusive. As molecular interaction and timeline of mammalian sex determination were mostly described in murine experiments, we generated a mouse model in which Sry was substituted with human SRY to verify the compatibility. The mouse model had the human SRY open reading frame at the locus of murine Sry exon 1 (Sry  (SRY) mice) and was generated using the CRISPR/Cas9 system. The reproductive system of the mice was analyzed. The expression of human SRY in the fetal gonadal ridge of Sry  (SRY) mice was detected. The external and internal genitalia of adult Sry  (SRY) mice were similar to those of wild-type females, without any significant difference in anogenital distance. Sry  (SRY) mice obtained gonads, which were morphologically considered as ovaries. Histological analysis revealed that the cortical regions of gonads from adult Sry  (SRY) mice contained few follicles. We successfully replaced genes on the Y chromosome with targeted genome editing using the CRISPR/Cas9 system. Since the Sry  (SRY) XY mice did not develop testis, we concluded that human SRY was insufficient to drive testis development in mouse embryos. The difference in response elements and lack of glutamine-rich domains may have invalidated human SRY function in mice. Signal transduction between Sry/SRY expression and Sox9/SOX9 activation is possibly organized in a species-specific manner.

Hippocampal morphology in the inbred mouse strains NZB and CBA/H and their reciprocal congenics for the nonpseudoautosomal region of the Y chromosome

1996 ◽  
Vol 26 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Pascale-Valérie Guillot ◽  
Frans Sluyter ◽  
Abdelkader Laghmouch ◽  
Pierre L. Roubertoux ◽  
Wim E. Crusio
Keyword(s):  
Y Chromosome ◽  
Inbred Mouse ◽  
Mouse Strains ◽  
Inbred Mouse Strains ◽  
Hippocampal Morphology
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