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Genetics
*** Shopping-Tip: Genetics
'''Genetics''' (from the
Greek language Greek genno '''γεννώ'''= give birth) is the
science of
genes,
heredity, and the
variation of
organisms. The word "genetics" was first suggested to describe the study of inheritance and the science of variation by the British scientist
William Bateson in a personal letter to
Adam Sedgwick, dated
April 18,
1905. Bateson first used the term "genetics" publicly at the Third International Conference on Genetics (London, England) in
1906.
Humans applied knowledge of genetics in prehistory with the
domestication and
selective breeding breeding of
plants and
animals. In modern research, genetics provides important tools for the investigation of the function of a particular gene, e.g., analysis of
genetic interactions. Within
organisms, genetic information generally is carried in
chromosomes, where it is represented in the
DNA sequence chemical structure of particular
DNA (deoxyribonucleic acid)
molecules.
Genes encode the information necessary for synthesizing the
amino-acid sequences in
proteins, which in turn play a large role in determining the final
phenotype, or physical appearance, of the organism. In
diploid organisms, a
dominant allele on one chromosome will mask the expression of a
recessive gene on the other.
The phrase '''to code for''' is often used to mean a gene contains the instructions about how to build a particular protein, as in ''the gene codes for the protein''.
The "one gene, one protein" concept is now known to be simplistic. For example, a single gene may produce multiple products, depending on how its
transcription (genetics) transcription is regulated. Genes code for the
nucleotide sequences in
messenger RNA mRNA,
transfer RNA tRNA and
ribosomal RNA rRNA, required for protein synthesis.
Genetics determines much (but not all) of the appearance of organisms, including humans, and possibly how they act.
Environmental differences and
randomness random factors also play a part.
Twin Monozygotic ("identical") twins, a
cloning clone resulting from the early splitting of an embryo, have the same DNA, but different
personality personalities and
fingerprints. Genetically-identical plants grown in colder
climates incorporate shorter and less-saturated
fatty acids to avoid stiffness.
History
{{main|History of genetics}}
In his paper "Versuche über Pflanzenhybriden" ("Experiments in Plant Hybridization"), presented in
1865 to the Brunn Natural History Society,
Gregor Mendel traced the inheritance patterns of certain traits in pea plants and showed that they could be described mathematically. Although not all features show these patterns of
Mendelian inheritance, his work suggested the utility of the application of statistics to the study of inheritance. Since that time many more complex forms of inheritance have been demonstrated.
The significance of Mendel's work was not understood until early in the twentieth century, after his death, when his research was re-discovered by other scientists working on similar problems.
Mendel did not understand the nature of inheritance. We now know that some heritable information is carried in
DNA. (
Retroviruses, including
influenza,
oncoviruses and
HIV, and many
plant viruses, carry information as
RNA.) Manipulation of DNA can in turn alter the inheritance and features of various organisms.
Timeline of notable discoveries
:
1859 Charles Darwin publishes ''
The Origin of Species''
:
1865 Gregor Mendel's paper, ''Experiments on Plant Hybridization''
:
1903 Chromosomes are discovered to be hereditary units
:
1905 British biologist
William Bateson coins the term "genetics" in a letter to Adam Sedgwick
:
1910 Thomas Hunt Morgan shows that genes reside on chromosomes
:
1913 Alfred Sturtevant makes the first genetic map of a chromosome
:
1913 Gene maps show chromosomes containing linear arranged genes
:
1918 Ronald Fisher publishes ''On the correlation between relatives on the supposition of Mendelian inheritance'' - the
modern synthesis starts.
:
1927 Physical changes in genes are called
mutations
:
1928 Frederick Griffith discovers a hereditary molecule that is transmissible between bacteria (see
Griffiths experiment)
:
1931 Crossing over is the cause of
recombination (see
Barbara McClintock and
cytogenetics)
:
1941 Edward Lawrie Tatum and
George Wells Beadle show that genes code for
proteins; see the original
central dogma of genetics
:
1944 Oswald Theodore Avery,
Colin McLeod and
Maclyn McCarty isolate
DNA as the genetic material (at that time called
transforming principle)
:
1950 Erwin Chargaff shows that the four nucleotides are not present in nucleic acids in stable proportions, but that some general rules appear to hold (e.g., that the amount of adenine, A, tends to be equal to that of thymine, T).
Barbara McClintock discovers
transposons in
maize
:
1952 The
Hershey-Chase experiment proves the genetic information of
phages (and all other organisms) to be DNA
:
1953 DNA structure is resolved to be a double
helix by
James D. Watson and
Francis Crick, with the help of
Rosalind Franklin
:
1956 Jo Hin Tjio and
Albert Levan established the correct
chromosome number in humans to be 46
:
1958 The
Meselson-Stahl experiment demonstrates that DNA is
semiconservative replication semiconservatively replicated
:
1961 The
genetic code is arranged in triplets
:
1964 Howard Temin showed using
RNA viruses that Watson's
central dogma is not always true
:
1970 Restriction enzymes were discovered in studies of a bacterium, ''Haemophilius influenzae'', enabling scientists to cut and paste DNA
:
1977 DNA is
sequencing sequenced for the first time by
Fred Sanger,
Walter Gilbert, and
Allan Maxam working independently. Sanger's lab complete the entire genome of sequence of
Bacteriophage Phi-X174 phage Φ-X174;.
:
1983 Kary Banks Mullis discovers the
polymerase chain reaction enabling the easy amplification of DNA
:
1985 Alec Jeffreys discovers genetic finger printing.
:
1989 The first human gene is sequenced by
Francis Collins and
Lap-Chee Tsui. It encodes the
CFTR protein. Defects in this gene cause
cystic fibrosis
:
1995 The genome of ''
Haemophilus influenzae'' is the first genome of a free living organism to be sequenced
:
1996 Saccharomyces cerevisiae is the first
eukaryote genome sequence to be released
:
1998 The first genome sequence for a multicellular eukaryote, ''
C. elegans'' is released
:
2001 First draft sequences of the human genome are released simultaneously by the
Human Genome Project and
Celera Genomics.
:
2003 (
14 April) Successful completion of
Human Genome Project with 99% of the genome sequenced to a 99.99%
accuracy [http://www.genoscope.cns.fr/externe/English/Actualites/Presse/HGP/HGP_press_release-140403.pdf]
Areas of genetics
Classical genetics
:''Main articles:''
Classical genetics,
Mendelian inheritance
Classical genetics consists of the techniques and methodologies of
genetics that predate the advent of
molecular biology. After the discovery of the
genetic code and such tools of
Clone (genetics) cloning as
restriction enzymes, the avenues of investigation open to geneticists were greatly broadened. Some classical genetic ideas have been supplanted with the mechanistic understanding brought by molecular discoveries, but many remain intact and in use, such as
Mendelian inheritance Mendel's laws. Patterns of inheritance still remain a useful tool for the study of
genetic diseases.
Behavioral genetics
:''Main article:''
Behavioural genetics (British spelling)
Behavioral genetics studies the influence of varying genetics on animal behavior.
Clinical genetics
{{main|Clinical genetics}}
Physicians who are trained as Geneticists diagnose, treat, and counsel patients with
genetic disorders or
syndromes.
These doctors are typically trained in a genetics
Residency (medicine) residency and/or
fellowship.
Molecular genetics
{{main|Molecular genetics}}
Molecular genetics builds upon the foundation of classical genetics but focuses on the structure and function of
gene genes at a
Molecule molecular level. Molecular genetics employs the methods of both classical genetics (such as
hybridization) and
molecular biology. It is so-called to differentiate it from other sub fields of genetics such as
ecological genetics and
population genetics. An important area within molecular genetics is the use of molecular information to determine the patterns of descent, and therefore the correct
scientific classification of organisms: this is called
molecular systematics.
The study of inherited features not strictly associated with changes in the
DNA sequence is called
epigenetics.
Some take the view that
life can be defined, in
molecule molecular terms, as the set of strategies which
RNA polynucleotides have used and continue to use to perpetuate themselves. This definition grows out of work on the
origin of life, specifically the
RNA world hypothesis.
Population, quantitative and ecological genetics
:''Main articles:''
Population genetics,
Quantitative genetics,
Ecological genetics
Population, quantitative and ecological genetics are all very closely related subfields and also build upon classical genetics (supplemented with modern molecular genetics). They are chiefly distinguished by a common theme of studying
populations of organisms drawn from nature but differ somewhat in the choice of which aspect of the organism on which they focus. The foundational discipline is population genetics which studies the distribution of and change in
allele frequency allele frequencies of genes under the influence of the four evolutionary forces:
natural selection,
genetic drift,
mutation and
migration. It is the theory that attempts to explain such phenomena as
adaptation (biology) adaptation and
speciation.
The related subfield of quantitative genetics, which builds on population genetics, aims to predict the response to
selection given data on the
phenotype and relationships of individuals. A more recent development of quantitative genetics is the analysis of
quantitative trait loci. Traits that are under the influence of a large number of genes are known as quantitative traits, and their mapping to a location on the
chromosome requires accurate phenotypic, pedigree and marker data from a large number of related individuals.
Ecological genetics again builds upon the basic principles of population genetics but is more explicitly focused on
ecology ecological issues. While molecular genetics studies the structure and function of genes at a molecular level, ecological genetics focuses on wild populations of organisms, and attempts to collect data on the ecological aspects of individuals as well as molecular markers from those individuals.
Genomics
{{main|Genomics}}
A more recent development is the rise of
genomics, which attempts the study of large-scale genetic patterns across the
genome for (and in principle, all the DNA in) a given species. Genomics depends on the availability of whole genome sequences, and computational tools developed in the field of
bioinformatics for analysis of large set of data.
Closely-related fields
The science which grew out of the union of
biochemistry and genetics is widely known as
molecular biology.
The term "genetics" is often widely conflated with the notion of
genetic engineering, where the DNA of an organism is modified for some kind of practical end, but most research in genetics is aimed at understanding and explaining the effect of genes on phenotypes and in the role of genes in populations (see
population genetics and
ecological genetics), rather than genetic engineering.
See also
*
List of genetics-related topics
*
List of genetic engineering topics
*
Central dogma of molecular biology
*
Chimera (genetics) Chimerism
*
Gene regulatory network
*
Genetic counseling
*
Genetic screen
*
Genetic testing
*
List of publications in biology#Genetics Important publications in genetics
*
List of genetics research organizations
*
List of geneticists & biochemists
*
Mitochondrial genetics
*
Reprogenetics
*
Punnett square
Journals
*''
Genetics (journal) Genetics''
*''
Journal of Genetics''
*''
Annals of Human Genetics''
*''
Heredity (journal) Heredity''
External links
{{book|Genetics}}
{{commons|Category:Genetics}}
Related publications
*''Advanced Genetics''
-
''American Journal of Human Genetics''
*''Annual Reviews of Genetics''
-
''European Journal of Human Genetics''
*''[http://www.genesdev.org/ Genes and Development]''
-
''Human Molecular Genetics''
*''[http://jhered.oupjournals.org/ Journal of Heredity]''
-
''Latest Genetics News''
-
''Nature Genetics''
*''
Nature Reviews Genetics'' ([http://www.nature.com/nrg/index.html journal home])
-
''Nature Genome Gateway''
-
''Pharmacogenetics''
*''Journal of Medical Genetics''
Other
-
Everything you wanted to know about genetics — Provided by ''
New Scientist New Scientist''.
-
Exploring the Way Life Works
-
Genetic Science Learning Center
-
Letter to Adam Sedgwick in 1905 from William Bateson
-
The Virtual Library on Genetics
-
Council for Responsible Genetics
-
Genetics made easy
{{Genetics-footer}}
{{Biology-footer}}
Category:Genetics *
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see
Template:Genetics-footer
{{commonscat|Genetics}}
'''Genetics''' is the
science of
genes,
heredity, and the
variation of
organisms, as well as the
medicine medical practice of diagnosing, treating, and counseling patients with
genetic disorders. Humans began applying knowledge of genetics in prehistory with the
domestication and
selective breeding breeding of plants and animals. In modern research, genetics provides important tools in the investigation of the function of a particular gene, e.g. analysis of
genetic interactions. Within
organisms, genetic information generally is carried in
chromosomes, where it is represented in the
DNA sequence chemical structure of particular
DNA molecules.
{{catmore}}
Category:Biology
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ko:분류:ìœ ì „í•™
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