A paper on the research progress of gene map got high marks.

Gene mapping is an important link in genetic research, and the determination of gene mapping is helpful to understand the function of genes. The location of a gene is also helpful to the further location of other genes in the same chromosome or population; Gene mapping plays an important role in understanding the basis of genetic diseases in medical field, assisting the selection of genetic markers in animal production and mastering the genetic law of economic traits. In the research of transgenic technology in recent years, gene mapping is a necessary means to determine the integration position of donor gene and transgene in recipient chromosome. Just as the invention of maps has given us an understanding of the world, gene mapping is of epoch-making significance for human beings to deeply understand biological phenomena and laws.

With the development of gene mapping technology, the connotation of its concept is deepening. Early gene mapping mainly refers to distinguishing whether genes are linked or located on autosomes or sex chromosomes. At present, it includes genetic mapping to understand the relative position of genes in linkage groups and physical mapping to understand the specific position of genes on a chromosome. The content of mapping includes QTL gene and molecular genetic markers (mainly microsatellite loci, RFLP, etc. ) In addition to quality trait genes. There are many methods for gene chromosome location, among which the main physical methods include traditional fluorescence in situ hybridization (fish) and radiation hybridization (RH). Although FlSH technology can locate gene chromosomes, from the molecular point of view, its location work is still rough, and RH location accuracy is higher than FlSH location. It is a new method of gene chromosome location with low cost and high efficiency, and it plays an increasingly important role in genetic research.

Then we can discuss the gene map from one direction:

Such as rice:/periodic _ xmdxxb200706023.aspx.

Pig: At present, somatic hybrid cell lines used for physical location of pig genes are: French pig? Radiation hybridization clone plate (INRA- Minnesota pig radiation hybridization plate) is a pig radiation hybridization plate jointly constructed by pig × rodent somatic hybridization plate (SCP), French Academy of Agricultural Sciences and University of Minnesota (IMpRH), Susscrofa radiation hybridization plate (SSRH) in Japan, Roslin Research in Britain and Cambridge University (lin li, 2004). At present, the first two are widely used, and the similarity between them is that they are all based on PCR typing, which is convenient and fast.

Pigs? The rodent somatic hybrid plate was constructed by the French Academy of Agricultural Sciences (Labatoire de Gé né tique celluare, INRA, Castanet-Tolosan, France) and consists of 27 hybrid cell lines (Yerle et al., 1996). The donor cells used in the somatic hybridization plate were porcine lymphocytes or fibroblasts, then fused with China hamster xanthine phosphoribosyltransferase-deficient (HPRT-) cell line (1- 19 hybrid cell line) and mouse thymine kinase-deficient (TK-) cell line (20-27 hybrid cell line), and finally identified by cytogenetic method. The genotyping results of a gene in 27 hybrid cell lines were detected by PCR, and then the corresponding analysis was carried out with pig chromosomes or fragments of each hybrid cell line, so that the regional localization results of the gene on pig chromosomes could be obtained (Chevaliet et al., 1997). This method can only locate the gene in a rough chromosome position.

Porcine radiation hybridization clone plate IMpRH was constructed by French Academy of Agricultural Sciences and University of Minnesota (Yerle et al., 1998). After 7000 rads of radiation, donor cells of porcine lymphocytes or fibroblasts were fused with recipient cells of China hamster, and 152 hybrid cell clones were obtained. A set of porcine radiation hybridization plates (Yerle et al., 198+08 hybrid cell line) covering the whole pig genome was obtained by cytogenetic identification of the size and length of chromosomes or fragments in each hybrid cell line with FISH (small staggered repeat element) as a probe and specific SINE as a primer. Hawken et al. (1999) analyzed more than 900 Ⅰ with IMpRH.

The first generation pig genome-wide radiation hybridization map was constructed by using class ⅰ and class ⅱ markers. The map * * * consists of 128 linkage groups (the coordinate minimum LOD value is 4.8) and 59 individual markers, covering all autosomes and X chromosomes. The theoretical resolution is 145kb, and the average survival rate is 29.3%, with an average of about 70 kb/cR. The construction of the first radiation hybridization map of pigs provided abundant DNA coordinates for the location of new DNA markers and laid the foundation for the construction of high-resolution physical map of pig genome, so this set of cloning plates was widely used. As RH method is a positioning method based on PCR typing detection technology combined with Internet, for the IMpRH plate cloned from 1 18, under the conditions of specific primers, high amplification efficiency and stable conditions, the analysis results can be submitted to the corresponding website within one day and the final positioning results can be obtained, so it has the characteristics of rapidity, simplicity and high positioning accuracy, and the results are comparable. Compared with the linkage map, the radiation hybridization clone plate can locate and arrange the markers relatively accurately, and can cluster the indistinguishable markers within 5cM in the genetic linkage map (Rohrer et al.,1996; Hawken et al.,1999; Lin li, 2004). In addition to locating specific DNA markers, with the massive growth of ESTs database, RH method also shows broad application prospects in locating ESTs. Cirera et al. (2003) successfully located 2 14 ESTs from small intestine cDNA library by IMpRH. Tuggle et al. (2003) also used IMpRH to locate 64 ESTs mainly expressed in reproductive organs of sows.

I hope this helps.