When species interbreed, the hybrid offspring that are produced are often sterile. If only one hybrid sex is sterile, it is almost always the heterogametic (XY or ZW) sex. Taking this trend into account, the predominant model used to explain the genetic basis of F1 sterility involves a deleterious interaction between recessive sex-linked loci from one species and dominant autosomal loci from th...

BACKGROUND Interspecific hybrid crosses often produce offspring with reduced but non-zero survivorship. In this paper we ask why such partial inviability occurs. This partial inviability could arise from incomplete penetrance of lethal Dobzhansky-Muller incompatibilities (DMIs) shared by all members of a hybrid cross. Alternatively, siblings may differ with respect to the presence or number of ...

Rice (Oryza sativa L.) is one of the most important crops in the world. It is essential to develop an efficient method to build the fingerprinting database of commercial hybrid rice cultivars and their parental lines in seed market for rapid and unambiguous cultivar identification and seed purity analysis as new similar cultivars increasing yearly. The objective of this investigation were to fi...

The inability of mouse cell hybrids derived from two malignant parental cells to produce tumors in syngeneic F1 hosts was analyzed. YC hybrids, derived from the fusion of C1.1D and L1210 clls, failed to induce any tumor in adult mice, while 91% of x-irradiated newborn mice developed tumors and died. Some telocentric chromosomes were lacking in hybrid tumors; however, none of the immunologically...

The hybrid between Brassica napus and B. rapa displays obvious heterosis in both growth performance and stress tolerances. A comparative transcriptome analysis for B. napus (A(n)A(n)CC genome), B. rapa (A(r)A(r) genome), and its hybrid F1 (A(n)A(r)C genome) was carried out to reveal the possible molecular mechanisms of heterosis at the gene expression level. A total of 40,320 nonredundant unige...

Crossing experiments in mice with two human species of Schistosoma japonicum (Taiwan strain) and Schistosoma mansoni (Puerto Rican strain) were performed. The hybrid miracidia from the cross between female S. japonicum and male S. mansoni infected both Biophalaria glabrata and Oncomalania h. chiui. However, those from the reciprocal crossing could infect only B. glabrata. B. glabrata infected w...

House mice (Mus musculus domesticus) in Tunisia consists of two races, one carries the 40-acrocentric standard karyotypes and the other one is a robertsonian race (2n=22) homozygous for nine centric fusions (Rb). The F1 hybrids between the two chromosomal races showed a significant decrease in reproductive success and litter size. Such results can be related to the formation of meiotic trivalen...

Neonatal gonadeetomy has been used in some inbred strains of mice (7, 8, 10, 13-17) as an experimental tool to study the effect of hormonal imbalance. ~I'he effect of neonatal gonadectomy in reciprocal hybrid mice of several inbred strains has been described (11, 1~). This paper will report the response to gonadectomy of the F1 animals of strain DE X strain DBA and will compare the response of ...

The question as to whether prior irradiation or injection of cytotoxic drugs is essential for the development of spleen colonies was examined in genetically normal mice. Mixtures of lymph node and bone marrow cells from C57BL mice were injected into (C57BL X CBA-T6T6) F1 hybrid mice without pretreatment. Hematopoietic nodules were observed in the spleens of F1 hybrid mice killed 18 days after i...