Boveri-Sutton chromosome theory
Encyclopedia
The Boveri–Sutton chromosome theory (also known as the chromosome theory of inheritance or the Sutton-Boveri Theory) is a fundamental unifying theory of genetics
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....

 which identifies chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...

s as the carriers of genetic material
Gênes
Gênes is the name of a département of the First French Empire in present Italy, named after the city of Genoa. It was formed in 1805, when Napoleon Bonaparte occupied the Republic of Genoa. Its capital was Genoa, and it was divided in the arrondissements of Genoa, Bobbio, Novi Ligure, Tortona and...

. It correctly explains the mechanism underlying the laws of Mendelian inheritance
Mendelian inheritance
Mendelian inheritance is a scientific description of how hereditary characteristics are passed from parent organisms to their offspring; it underlies much of genetics...

 by identifying chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...

s with the paired factors
Allele
An allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...

 (particles) required by Mendel's laws. It also states that chromosomes are linear structures with gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

s located at specific sites along them.

It states simply that chromosomes, which are seen in all dividing cells and pass from one generation to the next, are the basis for all genetic inheritance.

Background

In 1879 Walther Flemming
Walther Flemming
Walther Flemming was a German biologist and a founder of cytogenetics.He was born in Sachsenberg near Schwerin as the fifth child and only son of the psychiatrist Carl Friedrich Flemming and his second wife, Auguste Winter...

 had discovered chromosomes and mitosis
Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...

 in salamander
Salamander
Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...

 eggs. August Weismann
August Weismann
Friedrich Leopold August Weismann was a German evolutionary biologist. Ernst Mayr ranked him the second most notable evolutionary theorist of the 19th century, after Charles Darwin...

 then linked meiosis with Mendelian inheritance in his germ plasm theory. This proposed the Weismann barrier
Weismann barrier
The Weismann barrier is the principle that hereditary information moves only from genes to body cells, and never in reverse. In more precise terminology hereditary information moves only from germline cells to somatic cells .This does not refer to the central dogma of molecular biology which...

, which prevented germ line
Germ cell
A germ cell is any biological cell that gives rise to the gametes of an organism that reproduces sexually. In many animals, the germ cells originate near the gut of an embryo and migrate to the developing gonads. There, they undergo cell division of two types, mitosis and meiosis, followed by...

 reproductive cells from passing on adaptive traits acquired by somatic cell
Somatic cell
A somatic cell is any biological cell forming the body of an organism; that is, in a multicellular organism, any cell other than a gamete, germ cell, gametocyte or undifferentiated stem cell...

s during an organism's life, ruling out Lamarckian
Jean-Baptiste Lamarck
Jean-Baptiste Pierre Antoine de Monet, Chevalier de la Marck , often known simply as Lamarck, was a French naturalist...

 inheritance. However, Weismann did not identify the meiotic chromosomes as Mendel's factors of inheritance (as Sutton and Boveri would later).

Attribution

The chromosome theory of inheritance is credited to papers by Walter Sutton
Walter Sutton
Walter Stanborough Sutton was an American geneticist and physician whose most significant contribution to present-day biology was his theory that the Mendelian laws of inheritance could be applied to chromosomes at the cellular level of living organisms...

 in 1902 and 1903, as well as to independent work by Theodor Boveri
Theodor Boveri
-External links:* Fritz Baltzer. . excerpt from . University of California Press, Berkeley; pp. 85–97....

 during roughly the same period. Boveri was studying sea urchin
Sea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...

s, in which he found that all the chromosomes had to be present for proper embryonic development to take place. Sutton's work with grasshopper
Grasshopper
The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...

s showed that chromosomes occur in matched pairs of maternal and paternal chromosomes which separate during meiosis and "may constitute the physical basis of the Mendelian law of heredity".

This groundbreaking work led E.B. Wilson in his classic text to name the chromosome theory of inheritance the "Sutton-Boveri Theory". Wilson was close to both men, since the young Sutton was his student and the prominent Boveri was his friend (in fact, Wilson dedicated the aforementioned book to Boveri). Although the naming precedence is now often reversed to "Boveri-Sutton", there are some who argue that Boveri didn't actually articulate the theory until 1904.

Verification

The proposal that chromosomes carried the factors of Mendelian inheritance was initially controversial, but in 1913 it gained strong support when Eleanor Carothers documented definitive evidence of independent assortment of chromosomes in a species of grasshopper. Debate continued, however, until 1915 when Thomas Hunt Morgan
Thomas Hunt Morgan
Thomas Hunt Morgan was an American evolutionary biologist, geneticist and embryologist and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries relating the role the chromosome plays in heredity.Morgan received his PhD from Johns Hopkins University in zoology...

's work on inheritance and genetic linkage
Genetic linkage
Genetic linkage is the tendency of certain loci or alleles to be inherited together. Genetic loci that are physically close to one another on the same chromosome tend to stay together during meiosis, and are thus genetically linked.-Background:...

 in the fruit fly Drosophila melanogaster
Drosophila melanogaster
Drosophila melanogaster is a species of Diptera, or the order of flies, in the family Drosophilidae. The species is known generally as the common fruit fly or vinegar fly. Starting from Charles W...

provided incontrovertible evidence for the proposal.

External links

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