In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA. The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as regulatory sequences, and often a substantial fraction of junk DNA with no evident function. Almost all eukaryotes have mitochondria and a small mitochondrial genome. Algae and plants also contain chloroplasts with a chloroplast genome.
A transposable element (TE), also transposon, or jumping gene, is a type of mobile genetic element, a nucleic acid sequence in DNA that can change its position within a genome, sometimes creating or reversing mutations and altering the cell's genetic identity and genome size.
Non-coding DNA (ncDNA) sequences are components of an organism's DNA that do not encode protein sequences. Some non-coding DNA is transcribed into functional non-coding RNA molecules. Other functional regions of the non-coding DNA fraction include regulatory sequences that control gene expression; scaffold attachment regions; origins of DNA replication; centromeres; and telomeres. Some non-coding regions appear to be mostly nonfunctional, such as introns, pseudogenes, intergenic DNA, and fragments of transposons and viruses. Regions that are completely nonfunctional are called junk DNA.
Barbara McClintock was an American scientist and cytogeneticist who was awarded the 1983 Nobel Prize in Physiology or Medicine. McClintock received her PhD in botany from Cornell University in 1927. There she started her career as the leader of the development of maize cytogenetics, the focus of her research for the rest of her life. From the late 1920s, McClintock studied chromosomes and how they change during reproduction in maize. She developed the technique for visualizing maize chromosomes and used microscopic analysis to demonstrate many fundamental genetic ideas. One of those ideas was the notion of genetic recombination by crossing-over during meiosis—a mechanism by which chromosomes exchange information. She produced the first genetic map for maize, linking regions of the chromosome to physical traits. She demonstrated the role of the telomere and centromere, regions of the chromosome that are important in the conservation of genetic information. She was recognized as among the best in the field, awarded prestigious fellowships, and elected a member of the National Academy of Sciences in 1944.
Prophase is the first stage of cell division in both mitosis and meiosis. Beginning after interphase, DNA has already been replicated when the cell enters prophase. The main occurrences in prophase are the condensation of the chromatin reticulum and the disappearance of the nucleolus.
Repeated sequences are short or long patterns that occur in multiple copies throughout the genome. In many organisms, a significant fraction of the genomic DNA is repetitive, with over two-thirds of the sequence consisting of repetitive elements in humans. Some of these repeated sequences are necessary for maintaining important genome structures such as telomeres or centromeres.
Retrotransposons are mobile elements which move in the host genome by converting their transcribed RNA into DNA through reverse transcription. Thus, they differ from Class II transposable elements, or DNA transposons, in utilizing an RNA intermediate for the transposition and leaving the transposition donor site unchanged.
John Brookfield,, is a British population geneticist. He is Professor of Evolutionary Genetics at the University of Nottingham, in the School of Biology.
Susan Randi Wessler, ForMemRS, is an American plant molecular biologist and geneticist. She is Distinguished Professor of Genetics at the University of California, Riverside (UCR).
Joachim Wilhelm "Jo" Messing was a German-American biologist who was a professor of molecular biology and the fourth director of the Waksman Institute of Microbiology at Rutgers University.
LTR retrotransposons are class I transposable elements (TEs) characterized by the presence of long terminal repeats (LTRs) directly flanking an internal coding region. As retrotransposons, they mobilize through reverse transcription of their mRNA and integration of the newly created cDNA into another genomic location. Their mechanism of retrotransposition is shared with retroviruses, with the difference that the rate of horizontal transfer in LTR-retrotransposons is much lower than the vertical transfer by passing active TE insertions to the progeny. LTR retrotransposons that form virus-like particles are classified under Ortervirales.
Sudha Bhattacharya is an Indian academic, scientist and a writer. She is recognized primarily for her in-depth study of Entamoeba histolytica, a parasitic protozoan that causes amoebiasis: Dr. Bhattacharya's laboratory first detected Ribosomal RNA genes on Circular DNA, while studying the parasite, and also discovered families of retrotransposons in the parasite genome. Her work has primarily been in the fields of Molecular Parasitology and Gene Regulation.
The McClintock Prize for Plant Genetics and Genome Studies is a prize awarded in genetics and genomics. The Prize is awarded by the Maize Genetics Executive Committee, and is presented to the Prize winner each spring at the Annual Maize Genetics Conference.
DNA transposons are DNA sequences, sometimes referred to "jumping genes", that can move and integrate to different locations within the genome. They are class II transposable elements (TEs) that move through a DNA intermediate, as opposed to class I TEs, retrotransposons, that move through an RNA intermediate. DNA transposons can move in the DNA of an organism via a single-or double-stranded DNA intermediate. DNA transposons have been found in both prokaryotic and eukaryotic organisms. They can make up a significant portion of an organism's genome, particularly in eukaryotes. In prokaryotes, TE's can facilitate the horizontal transfer of antibiotic resistance or other genes associated with virulence. After replicating and propagating in a host, all transposon copies become inactivated and are lost unless the transposon passes to a genome by starting a new life cycle with horizontal transfer. DNA transposons do not randomly insert themselves into the genome, but rather show preference for specific sites.
Kaustuv Sanyal is an Indian molecular biologist, mycologist and Director of Bose Institute in Kolkata. He is a professor at the Molecular Biology and Genetics Unit of the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR). He is known for his molecular and genetic studies of pathogenic yeasts such as Candida and Cryptococcus). An alumnus of Bidhan Chandra Krishi Viswavidyalaya and Madurai Kamaraj University from where he earned a BSc in agriculture and MSc in biotechnology respectively, Sanyal did his doctoral studies at Bose Institute to secure a PhD in Yeast genetics. He moved to the University of California, Santa Barbara, USA to work in the laboratory of John Carbon on the discovery of centromeres in Candida albicans. He joined JNCASR in 2005. He is a member of the Faculty of 1000 in the disciplines of Microbial Evolution and Genomics and has delivered invited speeches which include the Gordon Research Conference, EMBO conferences on comparative genomics and kinetochores. The Department of Biotechnology of the Government of India awarded him the National Bioscience Award for Career Development, one of the highest Indian science awards, for his contributions to biosciences, in 2012. He has also been awarded with the prestigious Tata Innovation Fellowship in 2017. The National Academy of Sciences, India elected him as a fellow in 2014. He is also an elected fellow of Indian Academy of Sciences (2017), and the Indian National Science Academy (2018). In 2019, he has been elected to Fellowship in the American Academy of Microbiology (AAM), the honorific leadership group within the American Society for Microbiology. He was awarded the J.C. Bose National Fellowship in 2020.
Michael Freeling is an American geneticist and plant biologist. He is currently a professor in the Department of Plant and Microbial Biology at the University of California. He is known for early work on maize anaerobic metabolism, developmental genetics of the maize ligule, proposing the grasses as a single genetic system model with Jeffrey Bennetzen, and the discovery of biased gene retention following whole genome duplications in plants. In 1994 Freeling was elected to the National Academy of Sciences. In 2017 he was awarded the McClintock Prize for Plant Genetics and Genome Studies.
Harold Edwin Umbarger was an American bacteriologist and biochemist.
Robert J. Schmitz is an American plant biologist and epigenomicist at the University of Georgia where he studies the generation and phenotypic consequences of plant epialleles as well as developing new techniques to identify and study cis-regulatory sequences. He is an associate professor in the department of genetics and the UGA Foundation Endowed Pant Sciences Professor.
Katrien M. Devos is an American plant geneticist who is distinguished research professor at the University of Georgia. Her research considers the structure, function and evolution of the genomes of grasses. In particular, Devos considers halophytic turfgrasses, cereals and bioenergy crops. She was elected Fellow of the American Association for the Advancement of Science in 2016.
Haig Hagop Kazazian Jr. was an American professor in the Department of Genetic Medicine at Johns Hopkins University School of Medicine in Baltimore, Maryland. Kazazian was an elected member of the National Academy of Sciences and the American Academy of Arts and Sciences.
