[Research progress in lampbrush chromosomes and some suggestions for their use in genetics teaching].

Lampbrush chromosomes (LBCs) are transient giant transcripts that exist at the diplotene stage of the first meiotic division in female gametocytes of almost all animals except mammals. LBCs are named for their lampbrush-like structure, however, they received the lowest research attention in studies of three classical cytogenetic chromosomes. They have been excellent models for studying the structure, organization, transcription, and transcriptional processing of chromosomes during meiosis. Here we briefly summarized these studies and LBCs forming mechanism and also discussed their possible functions, such as providing enough transcriptional products for embryonic development by oocytes LBCs or polyploidy demonstrated by previous reports. Finally, we discussed the possibility of introducing this typical case into our genetics teaching to inspire students' interest in genetics.

[Advances in understanding Drosophila salivary gland polytene chromosome and its applications in genetics teaching].

Drosophila salivary gland polytene chromosome, one of the three classical chromosomes with remarkable characteristics, has been used as an outstanding model for a variety of genetic studies since 1934. The greatest contribution of this model to genetics has been providing extraordinary angle of view in studying interphase chromosome structure and gene expression regulation. Additionally, it has been extensively used to understand some special genetic phenomena, such as dosage compensation and position-effect variegation. In this paper, we briefly review the advances in the study of Drosophila salivary gland chromosome, and try to systematically and effectively introduce this model system into genetics teaching practice in order to steer and inspire students' interest in genetics.

[Application of the Barr body case in teaching practice of genetics].

There are three classical problems at the chromosome level in cytogenetics, namely the formation mechanisms and effects of Barr body, polytenic chromosome, and lampbrush chromosome. Teachers and researchers keep sustaining attention to the Barr body because of the relationships between Barr body and the X chromosome dosage compensation effect in mammals, the human sex identification, and some human diseases. In our genetics teaching practice, we tried the case-based teaching method. We introduced the classical problems and research progress of the Barr body, as a line, into partial sections of our genetics teaching contents such as sex-linked genetic analysis, eukaryotic gene expression regulation, cancer genetic analysis, and genetic experiments. Finally, it will form a comprehensive summary of related knowledge of genetics through class discussion on the Barr body. We found that this teaching method can not only optimize the teaching contents of genetics, consolidate and widen students' basic knowledge, and help student to form the systemic and developmental views of a classical genetics problem, but also inspire students' interest in life sciences. Good teaching results have been achieved.

[Isolation and sequence analysis of a omega-gliadin homologous gene from wheat].

The DNA sequence of a full-length Triticum astivum CV. Jinan 177omega-gliadin homologous gene (omega1236) containing partial 5' and 3' flanking sequences with no intron was cloned by genomic PCR-based technology. The omega1236 sequence possibly encode a putative 47.2 kDa protein except for eight stop codons at amino acid residue positions 87, 117, 125, 157, 198, 313, 357 and 365 respectively. All the eight stop codons were caused by base transition. Sequence analysis revealed that omega1236 had 98% homology to a omega-gliadin gene of wheat (AB059812). Like all other gliadin gene families characterized in cereals, this gene possessed all the features in other plant reported previously. Phylogenetic analysis of the completely sequenced gene as well as those omega-genes in wheat, omega-secalin and C-horden genes in rye and barley, and alpha-, beta- and gamma-gliadin genes in wheat indicated that the omega1236 was more closely related to omega-gliadin gene family, much less homology to alpha- , beta- and gamma-gliadin gene families. Short peptide was produced in the culture of transformed E. coli induced by IPTG in early 2 h. It indicated that stop codon would be in omega1236. The result is consistent with that of the sequenced gene. The present paper could accumulate data useful for both omega-gliadin gene cloning by PCR and the study on structures and functions of these genes.