ISSN:0167-7063    

DOI:10.3109/01677068509100149

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

We report a developmental and genetic analysis of the X-linked vital locusl(1)EC7inDrosophila melanogaster. The locus maps in the salivary band region 1B4-5 to 1B8-9, a part of the X chromosome previously shown to be essential for normal neural development. Certain mutant alleles at the locus can cause embryonic lethality, indicating that the function provided by the gene is essential during embryo-genesis. A developmental analysis of gynandromorphic genetic mosaics shows that: (l)the gene function is autonomously essential in the eye; (2) the gene function is essential for normal development of the optic lobes; and (3) the gene function is not necessary in most major imaginal-disc cell derivatives with the exception of the eye disc. Conclusions from the developmental analysis of a temperature sensitive allele are consistent with those from the mosaic analysis. The embryonic lethality caused by the mutant alleles and abnormalities observed in the genetic mosaics have led us to rename the locusl(1)EC7toelav(embryonic lethal, abnormal visual system).

ISSN:0167-7063    

DOI:10.3109/01677068509100150

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

This study further analyzed the environmental and genetic mechanisms underlying the previously reported strain differences in tyrosine hydroxylase (TH) activity in the nigrostriatal and hypothalamic dopamine system of the BALB/cJ (B) and CBA/J (C) inbred mouse strains and related behavioral processes using parental and reciprocal F, hybrid generations. Significant strain differences were found in both sexes in all the measured characters. Comparing males and females, sexual dimorphisms were found in TH activity of substantia nigra (SN), corpus striatum (CS) and hypothalamus (H), and in exploratory behavior (IE). Presence of sexual dimorphism was genotype dependent, with the exception of TH activity in H. Major components of strain differences, maternal effects and additive gene effects, were separated by biometrical genetic methods. The analysis indicated that significant maternal effects were present in TH activity of H and CS with a trend towards this phenomenon in the SN. Additive gene effects were significant in all characters and various degrees of dominance were expressed in the hybrids in TH activity of SN and CS, as well as in behavioral traits, IE and spontaneous locomotion (SL). All the biochemical and behavioral parameters were expressed at lower levels in CBA/J than in BALB/cJ mice and reciprocal F, hybrids took intermediate positions between the two parental strains for all phenotypes examined, with the exception of IE, where complete dominance was found in (CXB)F, females. These results are consistent with the hypothesis that some of the genes affecting TH activity in brain dopamine systems contribute to the expression of dopamine mediated behaviors. Our analysis also indicates the possibility that the maternal effects on TH activity in CS and SN are the consequences of X-chromosome linked gene effects. We suggest that the influence of the X-chromosome linked gene(s) is dependent upon the action of gonadal steroids during the critical period of ontogenesis, and X-chromosome linked gene(s) play a major role in the genotype dependent expression of sexual dimorphism in TH activity.

ISSN:0167-7063    

DOI:10.3109/01677068509100151

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

In 3 families with the fragile-X [fra(X)] syndrome, we have identified a minimum of 4 recombinations in 9 meioses between the syndrome locus and the coagulation Factor IX gene. Two Factor IX intragenic restriction fragment length polymorphisms (RFLPs), produced withTaqI andXmnI, were used as markers. In lod score calculations, incomplete penetrance of the fra(X) mutation in males and females was taken into account by the computer program LIPED. The cumulative maximum lod score calculated from these data and from data previously reported was 2.75 at a recombination frequency of 20% (θ= 0.20). This indicates that the genetic distance between the Factor IX gene and the fra(X) locus is too great for Factor IX probes to be used alone for carrier detection in the fra(X) syndrome. Additional polymorphic loci more tightly linked to the fra(X) syndrome locus are required.

ISSN:0167-7063    

DOI:10.3109/01677068509100152

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor