遗传性听力损害基因研究进展

遗传性听力损害具有高度的遗传异质性,据估计与几百个基因有关。随着人类基因组计划的快速进展及为人类的健康事业提供的便利,遗传性听力损害相关基因的定位克隆工作近十年来取得了令人瞩目的进展。本文将简要介绍综合征型和非综合征型听力损害的核基因定位克隆和突变的研究进展,以及遗传性损害基因突变检测的临床应用情况。

DNA单分子的纳米定位切割与拾取研究

报道了一种对DNA单分子进行精细的纳米定位切割和拾取的技术。首先用分子梳技术将DNA拉直固定在经 3 氨基丙基三乙氧基硅烷修饰的云母基底上 ,然后通过精细控制原子力显微镜针尖与DNA样品之间的作用力 ,实现了对DNA链的定位切割和拾取。这种方法不仅可制备应用于临床遗传诊断和致病基因的定位等多种的微小DNA探针 。

The use of RAPD analysis to identify 4 main medicinal plants in Vitex

Objective： To identify the plants in Vitex including Vitex negundo L. , V. negundo var. cannabifolia （Sieb. et Zuee. ） Hand. -Mazz. , V. trifolia L. and V. trifolia L. var. simplicifolia Cham.. Methods： Both intra- and inter-species relationships among these plants were analyzed by RAPD marker. Twenty-one samples collected from different locations in China were tested using 25 RAPD arbitrary 10- mer primers which were screened from 32 primers. Cluster analysis was conducted by Ward＇s minimumvariance method of SAS software. Results： A total of 224 bands were produced and 128 bands showed polymorphism among 21 samples. The level of polymorphism within species was 51.7%. The dendrogram constructed based on RAPD analysis showed that 21 samples can be placed in 2 groups at the level of SPRS value of 0. 3636. The first group included V. trifolia var. simplicifolia and V. trifolia. The other consisted of V. negundo and V. negundo var. cannabifolia.. At the level of SPRS value of 0. 1, 21 samples can be obviously divided into 3 groups. V. trifolia and V. trifolia var. simplicifolia were clustered into one group, V. negundo and V. negundo var. cannabifolia were separately clustered to 2 groups. Conclusion： RAPD analysis is in good agreement with the traditional plant taxonomic classification, and fundamentally identical with their origins and morphologie characteristics, which indicates that the genetic relationship among samples is related to their center of origin. These medicinal species in Vitex have their specific bands which are available to identify. These specific bands can be used as species-specific molecular markers of Fruetus Vitieis for the application of germplasm identification and classification.

Cytogenetic Diagnosis and Analysis of the Clinical Profile of Individuals with Non-down Syndrome Intellectual Disability

Chromosomal alterations are the main causes of genetic diseases. One of the characteristics of certain genetic syndromes is ID （intellectual disability） presented by the individual in varying degrees. The study of the ID, its etiology, association or not with chromosomal abnormalities and a clinical diagnosis associated with the examination of karyotype are important aspects to consider when providing genetic counseling for families. Due to the lack of similar studies and of easy access to cytogenetic services for the Amazonian population, this study aimed to contribute to the advancement of this line of study in the state, analyzing the karyotype of individuals with ID, not Down Syndrome treated at the APAE-Manaus and identifying the main types of chromosomal alterations in the individuals analyzed. Analyzes were performed of the clinical diagnosis through investigation of the data from the interview and medical records as well as analysis of the karyotype of 31 patients with non-Down syndrome ID, attended in the APAE-Manaus. Of these subjects, 20 were female and 11 male. The results showed only 2 cases of chromosome abnormalities are detectable by classical cytogenetics, one of mosaic Turner syndrome and one a heterochromatic variant. It is therefore necessary to complement the study with the addition of molecular techniques for the investigation of microdeletions and/or other alterations not detectable through the banding technique, mainly for individuals whose dysmorphisms indicate a suspected syndrome.

Epigenetics of human melanoma： promises and challenges

Melanoma is the deadliest form of skin cancer with rising incidence and mortality rates. Although early-stage melanoma is highly curable, advanced-stage melanoma is refractory to treatment. This underscores the importance of prevention and early detection as well as the need to improve treatment and prognostication of human melanoma. Elucidating the underlying mechanisms of the initi- ation and progression of human melanoma can help identify potential targets of intervention for prevention, diagnosis, therapy, and prognosis of this disease. Aberrant DNA methylation and histone modifications are the best-established epigenetic mechanisms of carcinogenesis. The occurrence of epigenetic changes prior to clinical diagnosis of cancer and their reversibility through pharmaco-logic/genetic approaches offer a promising avenue for basic and translational research on human melanoma. Candidate gene（s） or genome-wide aberrant DNA methylation and histone modifications have been observed in human melanoma tumor tissues and cell lines, and correlated to cellular and functional characteristics and/or clinicopathologicai features of this malignancy. The present review summarizes the published researches on aberrant DNA methylation and histone modifications in connection with human melanoma. Representative studies are highlighted to set forth the current state of knowledge, gaps in the knowledgebase, and future directions in these epigenetic fields of research. Examples of epigenetic therapy applied for human melanoma in vitro, and the challenges of its in vivo application for clinical treatment of solid tumors are discussed.