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Kinds of gene rearrangement
Kinds of gene rearrangement

... to the writer improbable mechanically. There would be needed an accuracy of position, in the two strands, of less than half a micron, with nothing to mark the breakage points. Without such accuracy, the crossing over would be unequal; which it is not (with one exception). Also the conditions require ...
Breeding of maize types with specific traits
Breeding of maize types with specific traits

... colour is controlled by a recessive gene y. If a dominant allele Y is present, instead of the recessive one, the kernel colour is yellow. Modern technological processing of white kernels requires that anthocyanin pigments producing yellow, red or blue colours must not be even traceable. The cob must ...
Entering the second century of maize quantitative genetics
Entering the second century of maize quantitative genetics

... surprising if some candidate genes are not rediscovered. Many of these candidate genes were also discovered by mutagenesis experiments, where mutants are generally selected based on their large phenotypic effect. If the effect size in nature is similar to that seen in Heredity ...
LOCATION OF THE CENTROMERES ON THE LINKAGE
LOCATION OF THE CENTROMERES ON THE LINKAGE

... MAPS O F MAIZE' E. G. ANDERSON AND L. F. RANDOLPH California Institute of Technology, Pasadena, California, and United States Department of Agriculture, Cornell University, Ithaca, N . Y . Received June 6 , 1945 ...
Mapping the genes that made maize
Mapping the genes that made maize

Meiosis - Aurora City Schools
Meiosis - Aurora City Schools

... *crossing over during prophase 1 *random orientation of *chromosomes during metaphase 1 ...
THE EFFECT OF STRUCTURAL HETEROZYGOSITY ON
THE EFFECT OF STRUCTURAL HETEROZYGOSITY ON

... INCE somewhere between 30 and 50 percent of the extant angiosperms are polyploids it is clear that the ploidy pathway to new plant forms is of vital importance in evolution, and therefore potentially so to the plant breeder. Nearly all existing polyploids, however, have been successful in becoming f ...
Chapter 21
Chapter 21

... fragment. The acentric fragment is lost during mitosis; this can be detected by the disappearance of dominant alleles in a heterozygote. Fusion between the broken ends of the chromosome generates dicentric chromosomes, which undergo further cycles of breakage and fusion. The fusion-breakage-bridge c ...
induction of instability at selected loci in maize
induction of instability at selected loci in maize

... The Ds in the cells possessing Ac can subsequently "jump out" creating variegation in the plants arising from this cross. The other half will posses the mutated a1m‐4 locus or recessive a1 allele expressing the colorless phenotype. 1:3 ratio will occur if the plants are not homozygous for the mutati ...
Slide 1
Slide 1

... teosinte populations based on isozyme allele frequencies. It allowed to pinpoint the mexican teosinte that had allele frequencies “essentially indistinguishable” from maize: Z. mays ssp parviglumis. (Doebley et al 1984). – Evidence at the molecular level: a study of the microsatelite diversity in ma ...
Snímek 1
Snímek 1

...  an inverted sequence of sister chromatid segregation occurs during meiosis  terminal satellite DNA repeat-enriched chromatin threads assist the pairwise movement and the linkage of homologous non-sister chromatids up to metaphase II to enable the faithful formation of haploid gametes ...
Biology WarmUp: Meiosis Vocabulary Review 1. What does it
Biology WarmUp: Meiosis Vocabulary Review 1. What does it

... Biology WarmUp: Meiosis Vocabulary Review 6. In fruit flies, the gene for star eye and speck wing are on the same chromosome, yet offspring from star-eyed, speckwinged parents often inherit star eyes without the speck wings. How is this possible? Make a diagram to illustrate the process that is res ...
Drosophila melanogaster Preferential Segregation of the Fourth
Drosophila melanogaster Preferential Segregation of the Fourth

... Other chromosomes are'being studied, including two crossover ones. These should throw light on the mechanism concerned, but are not yet ready to report on. An unexpected result is that these preferences are very much reduced in the male, though apparently still present. In the two best-studied cases ...
The Maize Genome Poster
The Maize Genome Poster

... half of the 20th century, maize geneticists had studied hundreds of mutants, mapped gene locations, cloned the first plant genes, and identified transposon-induced genome rearrangements among closely related maize varieties. Meanwhile, a physical map of the maize genome was populated with markers an ...
PowerPoint Presentation - LSU Museum of Natural Science
PowerPoint Presentation - LSU Museum of Natural Science

... copy of chromosome 4 had attached to the end of chromosome 2. It lost its centromere. Diagram all members of chromosomes II and IV during synapsis in Meiosis I -chromosomes replicated -two pairs of sister chromatids for II -one pair of sister chromatids for IV ...
PDF
PDF

... some of which I have, unlike Johnson, read through (Image 1). These recommendations form a tale of three successive intellectual utopias. In the first act, the precursors of molecular genetics take hold among physicists, in particular in those around Niels Bohr. In the second act, molecular genetics ...
Transgenic maize in Mexico
Transgenic maize in Mexico

... Transgenic Maize in Mexico: No Need for Concern According to pre-Hispanic traditions, gods gave native Mexicans the first maize seeds and from then on, and for thousands of years, maize has been a vital element to the Latin American cultures. Biologically, maize is an orphan plant and has only one r ...
Transposition - Pennsylvania State University
Transposition - Pennsylvania State University

... Mechanism for DNA-mediated transposition ...
1992 Genetics Society of America Medal: Maynard V. Olson.
1992 Genetics Society of America Medal: Maynard V. Olson.

... employee, he has been the liaison between the Maize Genetics Corporation Stock Center at the University of Illinois and the U.S.D.A., which has supported the Center. It has taken a large amount of time and a good deal of quiet diplomacy to keep theCenter functioning effectively. He has been the poin ...
Document
Document

... Evidence for the controlling effect of Ac came from varying the dosage of Ac in the triploid endosperm: 0, 1, 2, or 3 doses. The dosage of Ac controlled when Ds breakage would take place, but how did frequency of breaks alter in development. ...
What is a Karyotype?
What is a Karyotype?

... You can identify the gender of the person by looking at the sex chromosomes on the karyotype. XX Female XY Male ...
Barbara McClintock
Barbara McClintock

... During the next decade Dr. McClintock applied herself to a unique phenomenon in maize. It appeared that certain regions of a chromosome moved, or transposed, to other positions. When this happened, there was a corresponding change in pigment (color) production in the corn. The interpretation of her ...
probability and statistics
probability and statistics

... Barbara McClintock [1902-1992] was awarded the Nobel Prize for Medicine/Physiology for her discovery of transposable genetic elements in maize. Today, these DNA sequences are known to be present in all organisms and may be responsible for the overall organization of eukaryotic genomes (Pennisi 1998) ...


... Now the F1 are intercrossed to make an F2 generation. What are the expected phenotypes? Remember:determine what gametes can be produced Then combine gametes to make F2 ...
Journal #16
Journal #16

... No, this isn’t a list of the people on a new reality T.V. show. It’s a list of the people of “Genetic Social Studies” or, in other words, the people throughout history that have been responsible for some of greatest discoveries in the area of GENETICS! So, as we begin our investigation of those very ...
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Barbara McClintock



Barbara McClintock (June 16, 1902 – September 2, 1992) 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 in 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 among the best in the field, awarded prestigious fellowships, and elected a member of the National Academy of Sciences in 1944.During the 1940s and 1950s, McClintock discovered transposition and used it to demonstrate that genes are responsible for turning physical characteristics on and off. She developed theories to explain the suppression and expression of genetic information from one generation of maize plants to the next. Due to skepticism of her research and its implications, she stopped publishing her data in 1953.Later, she made an extensive study of the cytogenetics and ethnobotany of maize races from South America. McClintock's research became well understood in the 1960s and 1970s, as other scientists confirmed the mechanisms of genetic change and genetic regulation that she had demonstrated in her maize research in the 1940s and 1950s. Awards and recognition for her contributions to the field followed, including the Nobel Prize in Physiology or Medicine, awarded to her in 1983 for the discovery of genetic transposition; she is the only woman to receive an unshared Nobel Prize in that category.
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