scholarly journals A structural gene (Tcp-1) within the mouse t complex is separable from effects on tail length and lethality but may be associated with effects on spermatogenesis

1981 ◽  
Vol 38 (2) ◽  
pp. 115-123 ◽  
Author(s):  
Lee M. Silver
Keyword(s):  
Genetic Basis ◽  
Genetic Factors ◽  
Tail Length ◽  
Transmission Ratio Distortion ◽  
Transmission Ratio ◽  
Cell Protein ◽  
Wild Type ◽  
T Complex ◽  
Interaction Factor ◽  
Ratio Distortion

SUMMARYThe Tcp-1 gene is located within the t complex and codes for a major testicular cell protein called p63/6.9. All wild-type chromosomes carry the Tcp-1b allele which codes for a basic form of this protein, while all complete t haplotypes carry the Tcp-1a allele which codes for an acidic form of this protein. It is not clear whether the Tcp-1 gene is associated with phenotypic effects of t haplotypes on embryogenesis and/or spermatogenesis, since the genetic basis for these effects is extremely complex. The elegant analysis of Lyon & Mason (1977) has allowed the identification and separation of a family of genetic factors which interact to produce the observed phenotypes associated with various combinations of t haplotypes. The data summarized in this report indicate that the Tcp-1a locus is separable from all of the identified t haplotype factors except for one; a complete correlation has been obtained between Tcp-1a and a proximal t haplotype factor which is involved in effects on transmission ratio distortion. Two other novel points emerge from this analysis. First, it appears that the tail interaction factor and the proximal sperm factors represent distinct genetic loci. Second, the accumulated data lead to the proposal that the TOrl chromosome carries a short segment of t haplotype chromatin containing Tcp-1a and proximal sperm factors involved in transmission ratio distortion and sterility.

scholarly journals Gene dosage effects on transmission ratio distortion and fertility in mice that carry t haplotypes

1989 ◽  
Vol 54 (3) ◽  
pp. 221-225 ◽  
Author(s):  
Lee M. Silver
Keyword(s):  
Gene Dosage ◽  
Transmission Ratio Distortion ◽  
Transmission Ratio ◽  
Double Dose ◽  
Absolute Level ◽  
T Complex ◽  
Gene Dosage Effects ◽  
Ratio Distortion ◽  
The Individual ◽  
Very High

SummaryComplete t haplotypes can be transmitted at distorted ratios from heterozygous +/t male mice as a consequence of t-specific alleles at a series of t complex distorter loci (Tcd-1t through Tcd-4t) and a t complex responder locus. Partial t haplotypes that lack the Tcd-2t allele cannot be transmitted at the very high ratios characteristic of complete t haplotypes. The breeding studies reported here tested the possibility that the absence of Tcd-2t could be compensated for by the presence of double doses of other Tcdt alleles. The results indicate that a double dose of Tcd-4t alone will not work, but that a double dose of both Tcd-1t and Tcd-4t can promote a very high transmission ratio in the absence of Tcd-2t. These results suggest that the extent to which transmission ratios are distorted is dependent upon the absolute level of expression of the individual Tcd genes. Further studies of genotypic effects on transmission ratio distortion, as well as fertility, lead to the suggestion of a fifth t complex distorter (Tcd-5) locus within t haplotypes.

scholarly journals Distorter genes of the mouse t-complex impair male fertility when heterozygous

1987 ◽  
Vol 49 (1) ◽  
pp. 57-60 ◽  
Author(s):  
Mary F. Lyon
Keyword(s):  
Male Fertility ◽  
Genetic Background ◽  
Inbred Strains ◽  
Transmission Ratio Distortion ◽  
Chromosome 17 ◽  
Male Mice ◽  
Wild Type ◽  
T Complex ◽  
Ratio Distortion ◽  
Harmful Effects

SummaryMale mice heterozygous for two distorter genes, Tcd-1 and Tcd-2, of the mouse t-complex but homozygous wild type for the responder, were generated by crossing animals carrying the partial t-haplotypes th51 and th18 to inbred strains. The fertility of these males was then compared with that of their brothers carrying normal chromosome 17s. On three of the inbred backgrounds used, C3H/HeH, C57BL/6J and TFH/H, the th51th18 + / + + + males were significantly less fertile than their normal sibs. With the fourth inbred strain used, SM/JH, both types of male were nonnally fertile. This confirmed earlier preliminary findings that when both homologues of chromosome 17 carry wild-type alleles of the responder, heterozygosity for the distorter genes is sufficient to impair fertility, but the effect varies with genetic background. These results are consistent with the concept that both the transmission ratio distortion and the male sterility caused by the t-complex are due to harmful effects of the distorter genes on wild-type alleles of the responder.

scholarly journals LC2, the Chlamydomonas Homologue of the tComplex-encoded Protein Tctex2, Is Essential for Outer Dynein Arm Assembly

1999 ◽  
Vol 10 (10) ◽  
pp. 3507-3520 ◽  
Author(s):  
Gregory J. Pazour ◽  
Anthony Koutoulis ◽  
Sharon E. Benashski ◽  
Bethany L. Dickert ◽  
Hong Sheng ◽  
...  
Keyword(s):  
Transmission Ratio Distortion ◽  
Transmission Ratio ◽  
Wild Type ◽  
Gene Encoding ◽  
Ratio Distortion ◽  
Differential Binding ◽  
Phenotype Transformation ◽  
Essential Subunit ◽  
Complete Deletion ◽  
T Haplotype

Tctex2 is thought to be one of the distorter genes of the mouset haplotype. This complex greatly biases the segregation of the chromosome that carries it such that in heterozygous +/t males, the t haplotype is transmitted to >95% of the offspring, a phenomenon known as transmission ratio distortion. The LC2 outer dynein arm light chain ofChlamydomonas reinhardtii is a homologue of the mouse protein Tctex2. We have identified Chlamydomonasinsertional mutants with deletions in the gene encoding LC2 and demonstrate that the LC2 gene is the same as the ODA12 gene, the product of which had not been identified previously. Complete deletion of the LC2/ODA12 gene causes loss of all outer arms and a slow jerky swimming phenotype. Transformation of the deletion mutant with the cloned LC2/ODA12 gene restores the outer arms and rescues the motility phenotype. Therefore, LC2 is required for outer arm assembly. The fact that LC2 is an essential subunit of flagellar outer dynein arms allows us to propose a detailed mechanism whereby transmission ratio distortion is explained by the differential binding of mutant (t haplotype encoded) and wild-type dyneins to the axonemal microtubules oft-bearing or wild-type sperm, with resulting differences in their motility.

scholarly journals Restoration of the Mendelian transmission ratio by a deletion in the mouse chromosome 1 HSR

1998 ◽  
Vol 71 (2) ◽  
pp. 119-125 ◽  
Author(s):  
DIETER WEICHENHAN ◽  
BÄRBEL KUNZE ◽  
WALTHER TRAUT ◽  
HEINZ WINKING
Keyword(s):  
Transmission Ratio Distortion ◽  
Chromosome 1 ◽  
Transmission Ratio ◽  
Recovery Ratio ◽  
Wild Type ◽  
Variable Cluster ◽  
Ratio Distortion ◽  
Normal Transmission ◽  
Mendelian Transmission ◽  
Mouse Chromosome 1

The house mouse, Mus musculus, harbours a variable cluster of long-range repeats in chromosome 1. As shown in previous studies, some high-copy clusters such as the MUT cluster are cytogenetically apparent as a homogeneously staining region (HSR) and are associated with a distortion of the Mendelian recovery ratio when transmitted by heterozygous females. The effect is caused by a decreased viability of +/+ embryos. It is compensated by maternal or paternal MUT. In this study, a deletion derivative of MUT, MUTdel, shows normal transmission ratios and no compensating capability. In this respect, MUTdel behaves like a wild-type cluster. Hence, both properties – transmission ratio distortion and compensating capability – map to the deleted region. The deletion comprises three-quarters of the MUT HSR and does not extend to the nearest markers adjacent to the HSR.

scholarly journals Deletion analysis of male sterility effects of t–haplotypes in the mouse

1990 ◽  
Vol 56 (2-3) ◽  
pp. 179-183 ◽  
Author(s):  
Dorothea Bennett ◽  
Karen Artzt
Keyword(s):  
Male Sterility ◽  
Deletion Analysis ◽  
Transmission Ratio Distortion ◽  
Chromosome 17 ◽  
Transmission Ratio ◽  
Wild Type ◽  
Ratio Distortion ◽  
Very High

SummaryWe present data on the effects of three chromosome 17 deletions on transmission ratio distortion (TRD) and sterility of several t-haplotypes. All three deletions have similar effects on male TRD: that is, Tdel/tcomplete genotypes all transmit their t–haplotype in very high proportion. However, each deletion has different effects on sterility of heterozygous males, with Tor/t being fertile, Thp/t less fertile, and Torl/t still less fertile. These data suggest that wild-type genes on chromosomes homologous to f-haplotypes can be important regulators of both TRD and fertility in males, and that the wild-type genes concerned with TRD and fertility are at least to some extent different. The data also provide a rough map of the positions of these genes.

scholarly journals Targeted Mutagenesis of a Candidate t Complex Responder Gene in Mouse t Haplotypes Does Not Eliminate Transmission Ratio Distortion

Genetics ◽  
1996 ◽  
Vol 144 (2) ◽  
pp. 785-792
Author(s):  
U Kevin Ewulonu ◽  
Kerry Schimenti ◽  
Barbara Kuemerle ◽  
Terry Magnuson ◽  
John Schimenti
Keyword(s):  
Es Cells ◽  
Targeted Mutagenesis ◽  
Transmission Ratio Distortion ◽  
Transmission Ratio ◽  
Functional Assay ◽  
T Complex ◽  
Actual Nature ◽  
Splicing Pattern ◽  
Ratio Distortion ◽  
T Haplotype

Abstract Transmission ratio distortion (TRD) associated with mouse t haplotypes causes +/t males to transmit the t-bearing chromosome to nearly all their offspring. Of the several genes involved in this phenomenon, the t complex responder (Tcrt) locus is absolutely essential for TRD to occur. A candidate Tcrt gene called Tcpl0bt was previously cloned from the genetically defined Tcrt region. Its location, restricted expression in testis, and a unique postmeiotic alternative splicing pattern supported the idea that Tcp10bt was Tcrt. To test this hypothesis in a functional assay, ES cells were derived from a viable partial t haplotype, and the Tcp10bt gene was mutated by homologous recombination. Mutant mice were mated to appropriate partial t haplotypes to determine whether the targeted chromosome exhibited transmission ratios characteristic of the responder. The results demonstrated that the targeted chromosome retained full responder activity. Hence, Tcp10bt does not appear to be Tcrt. These and other observations necessitate a reevaluation of genetic mapping data and the actual nature of the responder.

scholarly journals Transmission Ratio Distortion Due to the bl Gene in Table Beet

2001 ◽  
Vol 126 (3) ◽  
pp. 340-343 ◽  
Author(s):  
Diane Austin ◽  
I.L. Goldman
Keyword(s):  
Single Gene ◽  
Recessive Gene ◽  
Segregation Ratio ◽  
Transmission Ratio Distortion ◽  
Transmission Ratio ◽  
Wild Type ◽  
Gene Model ◽  
Male Gametes ◽  
Ratio Distortion ◽  
The Individual

The bl gene conditions a blotchy phenotype (irregular sectors of red and white root color) in table beet (Beta vulgaris ssp. vulgaris). Segregation of the bl gene was found to be consistent with a single recessive gene, however, some evidence for a departure from a single gene model was observed when blbl plants were used as females. In this report, segregation of the bl gene was examined in greater detail in 10 F2 populations derived from crosses of red blotchy-rooted females (genotype blbl, denoted blotchy) with red-rooted males (BlBl, denoted red,), and 10 F2 populations derived from the reciprocal cross. In blbl × BlBl crosses, the proportion of red-rooted progeny was greater than 0.75 in seven of the crosses, and was significantly greater (P = 0.005) in three crosses. A test for heterogeneity was significant, indicating that the proportion of red-rooted progeny differed significantly in these 10 crosses. In BlBl × blbl crosses, the proportion of red-rooted progeny was <0.75 in seven of the crosses and there were no significant departures from the expected 3:1 ratio in any of the individual crosses. However, a pooled estimate of the segregation ratio showed a significant (P < 0.01) departure from the 3:1 ratio (pooled estimate = 0.71). These data demonstrate transmission ratio distortion at the bl locus when blbl plants are used as both females and males in matings with wild type plants, but the degree of distortion is greater when blbl plants are used as females. Ratio distortion in such crosses may be due to a variety of factors, including increased transmission of the bl gene through female or male gametes depending on the direction of the cross, reduced fitness of maternally derived blbl progeny, epigenetic phenomena, increased fitness of paternally derived blbl progeny, or linkage of the bl gene to viability genes.

scholarly journals A Chlamydomonas Homologue of the Putative Murine t Complex Distorter Tctex-2 Is an Outer Arm Dynein Light Chain

1997 ◽  
Vol 137 (5) ◽  
pp. 1081-1090 ◽  
Author(s):  
Ramila S. Patel-King ◽  
Sharon E. Benashski ◽  
Alistair Harrison ◽  
Stephen M. King
Keyword(s):  
Molecular Analysis ◽  
Light Chain ◽  
Meiotic Drive ◽  
Cytoplasmic Dynein ◽  
Transmission Ratio Distortion ◽  
Dynein Light Chain ◽  
Wild Type ◽  
Biochemical Model ◽  
T Complex ◽  
Ratio Distortion

Molecular analysis of a 19,000-Mr protein from the Chlamydomonas flagellum reveals that it is homologous to the t complex–encoded protein Tctex-2, which is a candidate for one of the distorter products that cause the extreme transmission ratio distortion (meiotic drive) of the murine t complex. The 19,000-Mr protein is extracted from the axoneme with 0.6 M NaCl and comigrates with the outer dynein arm in sucrose density gradients. This protein also is specifically missing in axonemes prepared from a mutant that does not assemble the outer arm. These data raise the possibility that Tctex-2 is a sperm flagellar dynein component. Combined with the recent identification of Tctex-1 (another distorter candidate) as a light chain of cytoplasmic dynein, these results lead to a biochemical model for how differential defects in spermiogenesis that result in the phenomenon of meiotic drive might be generated in wild-type vs t-bearing sperm.

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