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Quantitative trait loci (QTL) examination on the joinmap for agronomic and fiber quality traits revealed highly recombined and gene abundant regions on cotton chromosomes. The compilation of genetic linkage maps and joint maps from different breeding gene pools enabled partial dissection of the A and D subgenomes in G. hirsutum.

Microsatellite markers or simple sequence repeats are a new type of genetic marker for cotton.

Genetic manipulation of plant reproduction is limited by the lack of knowledge on genes controlling gametophyte development. We have combined the power of haploid analysis with the advanced technique of confocal laser scanning microscopy to identify and understand the genetic mechanism of pollen development in cotton. A study was made on the differential effects of specific chromosomal deficiencies on the morphology of mature cotton pollen. Pollen of the two tetraploid species (G. hirsutum L. and G. barbadense L.) were found to be morphologically distinct. Confocal microscopy was used to construct a three-dimensional image of the fluorochrome-stained pollen grains. Cytogenetically deficient stocks of cotton were used for locating genes for pollen development to chromosomes and chromosome arms. Results indicated that the pollen size and spine pattern were significantly different between TM-1 (G. hirsutum) and 3-79 (G. barbadense). Comparative analysis of pollen morphology of parental and interspecific hybrid, monosomic, and monotelodisomic plants indicated that gene(s) responsible for pollen spine development were located on the long arm of chromosome 12. The segregating nature of pollen morphological features indicated that the gametophytic gene(s) of the microspore partially controlled the pollen size and spine formation during pollen grain development., Plant Genome research is directed primarily towards linking sporophytic traits with their major controlling genes. One of the major limitations in the genetic manipulation of plant reproductive systems is the [...]

Chromosome substitution lines (CSLs) have been developed for selected chromosomes from two tetraploid species of Gossypium and are effective ways to target introgression of alleles from exotic tetraploid species into Upland cotton (G. hirsutum L.) Genetic effects of chromosomes 1, 4, and 18 from Upland cot- ton (TM-1), Pima cotton (G. barbadense L.), and Hawaiian cotton (G. tomentosum Nutt. ex Seem) were estimated by topcrossing TM-1 and six isochromosomal CSLs with fve upland cultivars and comparing F2 and F3 hybrids for agronomic and fiber traits. Data were analyzed according to an additive-dominance (AD) model. Additive genetic effects were greater than dominance effects for lint percentage, fiber uniformity, fiber strength, and elongation; whereas, dominance effects were greater than additive effects for boll weight, lint yield, fiber length, and fiber micronaire. All additive x environment effects were small. Dominance x environment effects were only significant for boll weight, lint yield, and fiber micronaire. Chromosome B04 and B18 from Pima cotton and T01 from Hawaiian cotton had significantly greater additive effects for lint percentage than homologs. Chromosomes 1, 4, and 18 from the three species generally showed negative additive effect on lint yield compared with cultivars. Chromosome 1 from Hawaiian cotton had greater additive effects on fiber length than homologs. Chromosomes 1 and 4 from Pima cotton showed greater additive effects on fiber strength than homologs. The magnitude of additive effects on important agronomic and fiber traits show that Pima cotton and Hawaiian cotton harbor useful alleles for Upland cotton breeding programs. [ABSTRACT FROM AUTHOR]

This article presents information on the registration of 17 upland cotton germplasm lines disomic for different Gossypium barbadense chromosome or arm substitutions. Seventeen germplasm lines were each developed by hypoaneuploid-based backcross substitution of a different Gossypium barbadense chromosome or chromosome segment into a Gossypium hirsutum genetic background by the Texas Agricultural Experiment Station, the U.S. Department of Agriculture-ARS, and the Mississippi Agricultural and Forestry Experiment Station and released in 2004. The substitution lines are genetically similar to TM-1, an Upland cotton genetic standard, and to each other, except that each line differs by the replacement of a specific homologous pair of chromosomes or chromosome segments from the donor line 3-79, a Gossypium barbadense genetic standard. These germplasm lines were released because attempts to incorporate genes from Gossypium barbadense for exceptional fiber length, strength, and fineness into Upland cotton have generally not achieved stable introgression. The development of CS-B lines was based on principles of cotton cytogenetic behavior, transmission, and inheritance.

Two bovine BAC clones were identified by PCR as containing the bovine gene PRKCI. Both clones were assigned by FISH to bands q34→q36 on BTA1. The sequence information derived from genomic DNA and from both clones was identical and showed a high degree of homology to human PRKCI (HSAXq21.3, 95.5% homology), and mouse Prkcl (MMU3, 13.8 cM, 87.6% homology) and rat Prkcl (88.8% homology). This assignment could suggest a disruption of the synteny conservation of mammalian X-linked genes, but most likely suggests a misassignment of this gene to the human X. Copyright © 2002 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Here we report the physical assignment of 40 microsatellite markers by fluorescence in situ hybridization to 13 different bovine chromosomes. This information will be valuable in providing physically anchored landmarks for the construction of contigs throughout the bovine genome. It also is useful for the purpose of integrating the linkage maps of these chromosomes to their physical maps and determining the physical coverage of these linkage groups. Copyright © 1999 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract Background Cultivated cotton is an annual fiber crop derived mainly from two perennial species, Gossypium hirsutum L. or upland cotton, and G. barbadense L., extra long-staple fiber Pima or Egyptian cotton. These two cultivated species are among five allotetraploid species presumably derived monophyletically between G. arboreum and G. raimondii. Genomic-based approaches have been hindered by the limited variation within species. Yet, population-based methods are being used for genome-wide introgression of novel alleles from G. mustelinum and G. tomentosum into G. hirsutum using combinations of backcrossing, selfing, and inter-mating. Recombinant inbred line populations between genetics standards TM-1, (G. hirsutum) × 3-79 (G. barbadense) have been developed to allow high-density genetic mapping of traits. Results This paper describes a strategy to efficiently characterize genomic variation (SNPs and indels) within and among cotton species. Over 1000 SNPs from 270 loci and 279 indels from 92 loci segregating in G. hirsutum and G. barbadense were genotyped across a standard panel of 24 lines, 16 of which are elite cotton breeding lines and 8 mapping parents of populations from six cotton species. Over 200 loci were genetically mapped in a core mapping population derived from TM-1 and 3-79 and in G. hirsutum breeding germplasm. Conclusion In this research, SNP and indel diversity is characterized for 270 single-copy polymorphic loci in cotton. A strategy for SNP discovery is defined to pre-screen loci for copy number and polymorphism. Our data indicate that the A and D genomes in both diploid and tetraploid cotton remain distinct from each such that paralogs can be distinguished. This research provides mapped DNA markers for intra-specific crosses and introgression of exotic germplasm in cotton.

This article was migrated. The article was marked as recommended. Intimate partner violence (IPV) is a global public health problem that has been exacerbated by the social isolation measures currently in place in countries around the world. The authors appreciate the importance of teaching medical students the skill sets to cope with the recognition and diagnosis and medical management of IPV. This is because physicians are most often the first point of contact for victims of IPV. It is also essential to ensure medical students become self-aware of the emotional triggers which may be associated with caring for victims of IPV. This opinion piece explains how medical educators can make a difference in training future physicians in caring for victims of IPV. With the current COVID-19 pandemic bringing the issue of IPV sharply into focus, this paper outlines why medical educators should ensure that medical students are equipped to deal with the societal consequences emanating from the COVID-19 pandemic which will reverberate into the future. Therefore, there is no more time to waste. We are facing a critical juncture, with the current cohort of medical students and physicians exposed to the disproportionately high levels of personal, professional, and emotional trauma that have resulted from the COVID-19 pandemic. Training is imperative; it is of paramount importance for our future medical professionals to be self-aware of their emotional triggers., (Copyright: © 2020 Dyer H et al.)

Key Message: A high-resolution GWAS detected consistent QTL for resistance to Verticillium wilt and Fusarium wilt race 4 in 376 U.S. Upland cotton accessions based on six independent replicated greenhouse tests. Verticillium wilt (VW, caused by Verticillium dahliae Kleb.) and Fusarium wilt (FOV, caused by Fusarium oxysporum f.sp. vasinfectum Atk. Sny & Hans) are the most important soil-borne fungal diseases in cotton. To augment and refine resistance quantitative trait loci (QTL), we conducted a genome-wide association study (GWAS) using high-density genotyping with the CottonSNP63K array. Resistance of 376 US Upland cotton accessions to a defoliating VW and virulent FOV4 was evaluated in four and two independent replicated greenhouse tests, respectively. A total of 15 and 13 QTL for VW and FOV4 resistances were anchored by 30 (on five chromosomes) and 56 (on six chromosomes) significant single nucleotide polymorphic (SNPs) markers, respectively. QTL on c8, c10, c16, and c21 were consistent in two or more tests for VW resistance, while two QTL on c8 and c14 were consistent for FOV4 resistance in two tests. Two QTL clusters on c16 and c19 were observed for both VW and FOV4 resistance, suggesting that these genomic regions may harbor genes in response to both diseases. Using BLAST search against the sequenced TM-1 genome, 30 and 35 candidate genes were identified on four QTL for VW resistance and on three QTL for FOV4 resistance, respectively. These genomic regions were rich in NBS-LRR genes presented in clusters. The results create opportunities for further studies to determine the correlations of field resistance with these QTL, molecular examinations of VW and FOV4 resistances, marker-assisted selection (MAS) and eventual cloning of QTL for disease resistance in cotton.