Jul 01, 2014 · Charles Darwin, while trying to devise a general theory of heredity from the observations of animal and plant breeders, discovered that domesticated mammals possess a distinctive and unusual suite of heritable traits not seen in their wild progenitors. Some of these traits also appear in domesticated birds and fish. The origin of Darwin’s “domestication syndrome” has remained a conundrum ...
- Adam S. Wilkins, Adam S. Wilkins, Richard W. Wrangham, W. Tecumseh Fitch
- Regions of Plant Domestication in The Americas
- Changes Associated with Domestication
- Genetic Control of Traits of The Domestication Syndrome
- Multiple Domestication and Multiple Origins of Domestication Traits
- Past Domestication as A Guide to Future Improvement of New World Crops
Domestication is generally considered to be the end-point of a continuum that starts with exploitation of wild plants, continues through cultivation of plants selected from the wild but not yet genetically different from wild plants, and terminates in fixation, through human selection, of morphological and hence genetic differences distinguishing a domesticate from its wild progenitor. These differences constitute the domestication syndrome and generally render the domesticate less capable of survival in the wild, thus dependent on man for its growth and reproduction. Features of the domestication syndrome include loss of dispersal, increase in size (especially of the harvested part of the plant), loss of seed dormancy and loss of chemical or mechanical protection against herbivores. Crops vary within and between species in their degrees of domestication. All known accessions of Capsicum pubescenshave large fruits that have lost their dispersal mechanism, and this species occurs onl...
Four regions are now generally considered to have been independent areas of crop domestication in the Americas: eastern North America, Mesoamerica, the Andean region and the tropical lowlands of South America. Table 1shows the approximate dates of the first appearance in the archaeological record of some of the cultigens associated with each region.
Schwanitz (1966), Purseglove (1968) and Hawkes (1983), among others, have provided comprehensive treatments of the changes occurring under domestication, so discussion here will centre on data gathered since these reviews.
Studies based on Mendelian genetics
Until recently, the genetic control of features distinguishing domesticated plants from their wild relatives had to be investigated by the classic Mendelian technique of crossing parents with different phenotypes and analysing ratios in the segregating progeny. Many of the qualitative changes associated with domestication were thereby found to be controlled by one or a few major genes, for example loss of seed dispersal and change to determinate habit in domesticated common bean (Koinange et...
DNA markers and the study of quantitative trait loci
A major advance in the study of the genetics of domestication came with the development of DNA markers, which made it possible to produce saturated linkage maps for many crops and then to determine, by looking for associations with these markers, how many and which regions of the genome carry factors affecting a given quantitative trait (quantitative trait loci or QTLs). In this way, 28 different QTLs affecting fruit weight in tomato have been located, though alleles at just one of these (fw2...
Orthologies of genes involved in domestication
The markers used to construct a saturated linkage map of one species may be used to construct linkage maps for other crops in the same family. By this means, it has been possible to compare the position of QTLs involved in the domestication syndrome in maize, sorghum and rice (Paterson et al., 1995), and in aubergine, tomato and chile pepper (Doganlar et al., 2002). In both groups, QTLs controlling similar traits map to the same conserved regions of the genome, suggesting that changes at the...
A feature of crop domestication in the Americas is the number of examples of independent domestication of different species in the same genus, or occasionally of the same species (Table 2). New World crops are therefore potentially useful resources for investigating the still-unresolved question of whether similar changes have been selected independently, resulting in parallel or convergent evolution of the domestication syndrome, or whether different mutations have been selected in different regions, so that similar phenotypes are actually controlled by different genotypes. Prior to the advent of molecular genetics, this question could be addressed only by crossing the related domesticates. If the F1 shows the wild-type phenotype, then the two domesticates are assumed to carry mutations at different, complementary, loci and thus to have evolved the trait in question independently. Cheng (1989) crossed a non-pungent bell pepper (Capsicum annuum) with a non-pungent accession of the c...
The developing understanding of the genetic control of various traits of the domestication syndrome and of the mode of action of some of the genes involved may assist in realizing the potential of some of the minor domesticates of the New World. Crops such as goldenberry (Physalis peruviana), pepino (Solanum muricatum) and yam bean (Pachyrhizus erosus) command high prices in markets in some developed countries (National Research Council, 1989), so are potentially useful export-earners for the developing countries in which they originated. Naranjilla (Solanum quitoense) and cupuaçu (Theobroma grandiflorum) have attracted the attention of commercial companies in developed countries, but problems of reliably producing large quantities of fruit have led to loss of potentially valuable export markets (National Research Council, 1989; Smith et al., 1992). These and other lesser known domesticates need further improvement to adapt them to a wider range of environments, modify their morphol...
I am grateful to Duncan Vaughan and Charles Heiser for supplying some unpublished observations, and to three anonymous referees for helpful comments and suggestions of additional references to cite. Funding to pay the Open Access publication charges for this article was provided by the OECD.
- Barbara Pickersgill
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particular chromosome (trisomy, 2n+1).] Trisomies do occur in humans. The best known is Downs syndrome (trisomy of chromosome 21), which occurs in approximately 1/700 live births. Other much rarer trisomies are Patau Syndrome (trisomy 13) and Edwards Syndrome (trisomy 18). Individuals with trisomy 13 or 18 often die within the first few weeks ...
Oct 25, 2017 · Examples of numerical disorders include trisomy, monosomy and triploidy. Probably one of the most well-known numerical disorders is Down syndrome (trisomy 21). Other common types of numerical disorders include trisomy 13, trisomy 18, Klinefelter syndrome and Turner syndrome.
Dog domestication may be the result of just a few genetic changes, including ones that made canines more interested in interacting with people. ... All three are tied to Williams-Beuren syndrome ...
Down syndrome; Anthropometry; Trisomy 21: Â: Introduction: Â: Down syndrome (Trisomy 21) is one of the commonest chromosomal disorders which occur in one in 650-1000 live births. Mental retardation, dysmorphic facial features and other distinctive phenotypic traits characterize the Down syndrome . A precise diagnosis makes available all the ...
incipient domestication. W e analyse the cases of traditional greens called ‘quelites’ such as Anoda cristata and Cr otalaria pumila in which people distinguish favour-
Aug 01, 2007 · Because trisomy 8 is ordinarily present in only 14% of patients with myelodysplastic syndrome, this is a significant overrepresentation. We describe a patient with recurrent aphthous stomatitis who was subsequently diagnosed with trisomy 8–positive myelodysplastic syndrome after an unexplained macrocytosis was further investigated.
Jul 08, 2017 · Trisomy is a condition similar to triploidy. It occurs when only certain pairs of chromosomes (the 13 th, 18 th, and 21 st chromosomes being the most common) get an extra chromosome in every cell....