Evolution Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.Anti-spam check. Do not fill this in! == Sources of variation == {{main|Genetic variation}} {{further|Genetic diversity|Population genetics}} {{multiple image|direction=vertical|align=right|image1=Biston.betularia.7200.jpg |image2=Biston.betularia.f.carbonaria.7209.jpg|width=200|caption1=White [[peppered moth]] |caption2=Black morph in [[peppered moth evolution]]}} Evolution can occur if there is genetic variation within a population. Variation comes from mutations in the genome, reshuffling of genes through [[sexual reproduction]] and migration between populations ([[gene flow]]). Despite the constant introduction of new variation through mutation and gene flow, most of the genome of a species is very similar among all individuals of that species.<ref>{{cite journal |last1=Butlin |first1=Roger K. |last2=Tregenza |first2=Tom |date=28 February 1998 |title=Levels of genetic polymorphism: marker loci versus quantitative traits |journal=Philosophical Transactions of the Royal Society B |volume=353 |issue=1366 |pages=187–198 |doi=10.1098/rstb.1998.0201 |issn=0962-8436 |pmc=1692210 |pmid=9533123}} * {{cite journal |last1=Butlin |first1=Roger K. |last2=Tregenza |first2=Tom |date=29 December 2000 |title=Correction for Butlin and Tregenza, Levels of genetic polymorphism: marker loci versus quantitative traits |journal=Philosophical Transactions of the Royal Society B |volume=355 |issue=1404 |doi=10.1098/rstb.2000.2000 |issn=0962-8436 |quote=Some of the values in table 1 on p. 193 were given incorrectly. The errors do not affect the conclusions drawn in the paper. The corrected table is reproduced below. |page=1865 |ref=none|doi-access=free }}</ref> However, discoveries in the field of [[evolutionary developmental biology]] have demonstrated that even relatively small differences in genotype can lead to dramatic differences in phenotype both within and between species. An individual organism's phenotype results from both its genotype and the influence of the environment it has lived in.<ref name="Lin" /> The modern evolutionary synthesis defines evolution as the change over time in this genetic variation. The frequency of one particular allele will become more or less prevalent relative to other forms of that gene. Variation disappears when a new allele reaches the point of [[fixation (population genetics)|fixation]]—when it either disappears from the population or replaces the ancestral allele entirely.<ref name="Amos">{{cite journal |last1=Amos |first1=William |last2=Harwood |first2=John |date=28 February 1998 |title=Factors affecting levels of genetic diversity in natural populations |journal=[[Philosophical Transactions of the Royal Society B]] |volume=353 |issue=1366 |pages=177–186 |doi=10.1098/rstb.1998.0200 |issn=0962-8436 |pmc=1692205 |pmid=9533122}}</ref> === Mutation === {{main|Mutation}} [[File:Gene-duplication.svg|thumb|upright|Duplication of part of a [[chromosome]]]] Mutations are changes in the DNA sequence of a cell's genome and are the ultimate source of genetic variation in all organisms.<ref name="Futuyma2017c">{{harvnb|Futuyma |Kirkpatrick |2017 |pp=79–102 |loc=Chapter 4: Mutation and Variation}}</ref> When mutations occur, they may alter the [[gene product|product of a gene]], or prevent the gene from functioning, or have no effect. About half of the mutations in the coding regions of protein-coding genes are deleterious — the other half are neutral. A small percentage of the total mutations in this region confer a fitness benefit.<ref>{{ cite journal | last = Keightley | first = PD | date = 2012 | title = Rates and fitness consequences of new mutations in humans | journal = Genetics | volume =190 | issue = 2 | pages = 295–304 | doi = 10.1534/genetics.111.134668 | pmid = 22345605 | pmc = 3276617 }}</ref> Some of the mutations in other parts of the genome are deleterious but the vast majority are neutral. A few are beneficial. Mutations can involve large sections of a chromosome becoming [[gene duplication|duplicated]] (usually by [[genetic recombination]]), which can introduce extra copies of a gene into a genome.<ref>{{cite journal |last1=Hastings |first1=P. J. |last2=Lupski |first2=James R. |author-link2=James R. Lupski |last3=Rosenberg |first3=Susan M. |last4=Ira |first4=Grzegorz |date=August 2009 |title=Mechanisms of change in gene copy number |journal=Nature Reviews Genetics |volume=10 |issue=8 |pages=551–564 |doi=10.1038/nrg2593 |issn=1471-0056 |pmc=2864001 |pmid=19597530}}</ref> Extra copies of genes are a major source of the raw material needed for new genes to evolve.<ref>{{harvnb|Carroll|Grenier|Weatherbee|2005}}{{page needed|date=December 2014}}</ref> This is important because most new genes evolve within [[gene family|gene families]] from pre-existing genes that share common ancestors.<ref>{{cite journal |last1=Harrison |first1=Paul M. |last2=Gerstein |first2=Mark |author-link2=Mark Bender Gerstein |date=17 May 2002 |title=Studying Genomes Through the Aeons: Protein Families, Pseudogenes and Proteome Evolution |journal=[[Journal of Molecular Biology]] |volume=318 |issue=5 |pages=1155–1174 |doi=10.1016/S0022-2836(02)00109-2 |issn=0022-2836 |pmid=12083509}}</ref> For example, the [[human eye]] uses four genes to make structures that sense light: three for [[Cone cell|colour vision]] and one for [[Rod cell|night vision]]; all four are descended from a single ancestral gene.<ref>{{cite journal |last=Bowmaker |first=James K. |s2cid=12851209 |title=Evolution of colour vision in vertebrates |date=May 1998 |journal=Eye |volume=12 |issue=3b |pages=541–547 |doi=10.1038/eye.1998.143 |issn=0950-222X |pmid=9775215|doi-access=free }}</ref> New genes can be generated from an ancestral gene when a duplicate copy mutates and acquires a new function. This process is easier once a gene has been duplicated because it increases the [[Gene redundancy|redundancy]] of the system; one gene in the pair can acquire a new function while the other copy continues to perform its original function.<ref>{{cite journal |last1=Gregory |first1=T. Ryan |author-link1=T. Ryan Gregory |last2=Hebert |first2=Paul D. N. |author-link2=Paul D. N. Hebert |date=April 1999 |title=The Modulation of DNA Content: Proximate Causes and Ultimate Consequences |url=http://genome.cshlp.org/content/9/4/317.full |journal=[[Genome Research]] |volume=9 |issue=4 |pages=317–324 |doi=10.1101/gr.9.4.317 |issn=1088-9051 |pmid=10207154 |s2cid=16791399 |access-date=11 December 2014 |url-status=live |archive-url=https://web.archive.org/web/20140823063412/http://genome.cshlp.org/content/9/4/317.full |archive-date=23 August 2014|doi-access=free }}</ref><ref>{{cite journal |last=Hurles |first=Matthew |title=Gene Duplication: The Genomic Trade in Spare Parts |date=13 July 2004 |journal=[[PLOS Biology]] |volume=2 |issue=7 |page=e206 |doi=10.1371/journal.pbio.0020206 |issn=1545-7885 |pmc=449868 |pmid=15252449 |doi-access=free }}</ref> Other types of mutations can even generate entirely new genes from previously noncoding DNA, a phenomenon termed [[de novo gene birth|''de novo'' gene birth]].<ref>{{cite journal |last1=Liu |first1=Na |last2=Okamura |first2=Katsutomo |last3=Tyler |first3=David M. |last4=Phillips |first4=Michael D. |last5=Chung |first5=Wei-Jen |last6=Lai |first6=Eric C |date=October 2008 |title=The evolution and functional diversification of animal microRNA genes |journal=Cell Research |volume=18 |issue=10 |pages=985–996 |doi=10.1038/cr.2008.278 |issn=1001-0602 |pmc=2712117 |pmid=18711447 |display-authors=3}}</ref><ref>{{cite journal |last=Siepel |first=Adam |author-link=Adam C. Siepel |date=October 2009 |title=Darwinian alchemy: Human genes from noncoding DNA |journal=Genome Research |volume=19 |issue=10 |pages=1693–1695 |doi=10.1101/gr.098376.109 |issn=1088-9051 |pmc=2765273 |pmid=19797681}}</ref> The generation of new genes can also involve small parts of several genes being duplicated, with these fragments then recombining to form new combinations with new functions ([[exon shuffling]]).<ref>{{cite journal |last1=Orengo |first1=Christine A. |last2=Thornton |first2=Janet M. |s2cid=7483470 |author-link2=Janet Thornton |date=July 2005 |title=Protein families and their evolution—a structural perspective |journal=[[Annual Review of Biochemistry]] |publisher=[[Annual Reviews (publisher)|Annual Reviews]] |volume=74 |pages=867–900 |doi=10.1146/annurev.biochem.74.082803.133029 |issn=0066-4154 |pmid=15954844}}</ref><ref>{{cite journal |last1=Long |first1=Manyuan |last2=Betrán |first2=Esther |last3=Thornton |first3=Kevin |last4=Wang |first4=Wen |date=November 2003 |title=The origin of new genes: glimpses from the young and old |journal=Nature Reviews Genetics |volume=4 |issue=11 |pages=865–875 |doi=10.1038/nrg1204 |issn=1471-0056 |pmid=14634634|s2cid=33999892 }}</ref> When new genes are assembled from shuffling pre-existing parts, [[protein domain|domains]] act as modules with simple independent functions, which can be mixed together to produce new combinations with new and complex functions.<ref>{{cite journal |last1=Wang |first1=Minglei |last2=Caetano-Anollés |first2=Gustavo |author-link2=Gustavo Caetano-Anolles |date=14 January 2009 |title=The Evolutionary Mechanics of Domain Organization in Proteomes and the Rise of Modularity in the Protein World |journal=[[Structure (journal)|Structure]] |volume=17 |issue=1 |pages=66–78 |doi=10.1016/j.str.2008.11.008 |issn=1357-4310 |pmid=19141283|doi-access=free }}</ref> For example, [[polyketide synthase]]s are large [[enzyme]]s that make [[antibiotic]]s; they contain up to 100 independent domains that each catalyse one step in the overall process, like a step in an assembly line.<ref>{{cite journal |last1=Weissman |first1=Kira J. |last2=Müller |first2=Rolf |date=14 April 2008 |title=Protein–Protein Interactions in Multienzyme Megasynthetases |journal=[[ChemBioChem]] |volume=9 |issue=6 |pages=826–848 |doi=10.1002/cbic.200700751 |issn=1439-4227 |pmid=18357594|s2cid=205552778 }}</ref> One example of mutation is [[wild boar]] piglets. They are camouflage coloured and show a characteristic pattern of dark and light longitudinal stripes. However, mutations in the ''[[melanocortin 1 receptor]]'' (''MC1R'') disrupt the pattern. The majority of pig breeds carry MC1R mutations disrupting wild-type colour and different mutations causing dominant black colouring.<ref>{{Cite journal |last=Andersson |first=Leif |date=2020 |title=Mutations in Domestic Animals Disrupting or Creating Pigmentation Patterns |journal=Frontiers in Ecology and Evolution |volume=8 |doi=10.3389/fevo.2020.00116 |issn=2296-701X|doi-access=free }}</ref> === Sex and recombination === {{further|Sexual reproduction|Genetic recombination|Evolution of sexual reproduction}} In [[Asexual reproduction|asexual]] organisms, genes are inherited together, or ''linked'', as they cannot mix with genes of other organisms during reproduction. In contrast, the offspring of sexual organisms contain random mixtures of their parents' chromosomes that are produced through independent assortment. In a related process called [[homologous recombination]], sexual organisms exchange DNA between two matching chromosomes.<ref>{{cite journal |last=Radding |first=Charles M. |date=December 1982 |title=Homologous Pairing and Strand Exchange in Genetic Recombination |journal=[[Annual Review of Genetics]] |volume=16 |pages=405–437 |doi=10.1146/annurev.ge.16.120182.002201 |issn=0066-4197 |pmid=6297377}}</ref> Recombination and reassortment do not alter allele frequencies, but instead change which alleles are associated with each other, producing offspring with new combinations of alleles.<ref name="Agrawal">{{cite journal |last=Agrawal |first=Aneil F. |s2cid=14739487 |date=5 September 2006 |title=Evolution of Sex: Why Do Organisms Shuffle Their Genotypes? |journal=[[Current Biology]] |volume=16 |issue=17 |pages=R696–R704 |doi=10.1016/j.cub.2006.07.063 |issn=0960-9822 |pmid=16950096|bibcode=2006CBio...16.R696A |citeseerx=10.1.1.475.9645}}</ref> Sex usually increases genetic variation and may increase the rate of evolution.<ref>{{cite journal |last1=Peters |first1=Andrew D. |last2=Otto |first2=Sarah P. |date=June 2003 |title=Liberating genetic variance through sex |journal=[[BioEssays]] |volume=25 |issue=6 |pages=533–537 |doi=10.1002/bies.10291 |issn=0265-9247 |pmid=12766942}}</ref><ref>{{cite journal |last1=Goddard |first1=Matthew R. |last2=Godfray |first2=H. Charles J. |author-link2=Charles Godfray |last3=Burt |first3=Austin |date=31 March 2005 |title=Sex increases the efficacy of natural selection in experimental yeast populations |url=https://archive.org/details/sim_nature-uk_2005-03-31_434_7033/page/636 |journal=Nature |volume=434 |issue=7033 |pages=636–640 |bibcode=2005Natur.434..636G |doi=10.1038/nature03405 |issn=0028-0836 |pmid=15800622|s2cid=4397491 }}</ref> [[File:Evolsex-dia1a.svg|thumb|upright=1.15|This diagram illustrates the ''twofold cost of sex''. If each individual were to contribute to the same number of offspring (two), ''(a)'' the sexual population remains the same size each generation, where the ''(b)'' [[Asexual reproduction]] population doubles in size each generation.{{imagefact|date=December 2022}}]] The two-fold cost of sex was first described by [[John Maynard Smith]].<ref name="maynard">{{harvnb|Maynard Smith|1978}}{{page needed|date=December 2014}}</ref> The first cost is that in sexually dimorphic species only one of the two sexes can bear young. This cost does not apply to hermaphroditic species, like most plants and many [[invertebrate]]s. The second cost is that any individual who reproduces sexually can only pass on 50% of its genes to any individual offspring, with even less passed on as each new generation passes.<ref name="ridley">{{harvnb|Ridley|2004|p=314}}</ref> Yet sexual reproduction is the more common means of reproduction among eukaryotes and multicellular organisms. The [[Red Queen hypothesis]] has been used to explain the significance of sexual reproduction as a means to enable continual evolution and adaptation in response to [[coevolution]] with other species in an ever-changing environment.<ref name="ridley" /><ref name="red">{{cite journal |last=Van Valen |first=Leigh |author-link=Leigh Van Valen |year=1973 |title=A New Evolutionary Law |url=https://dl.dropboxusercontent.com/u/18310184/evolutionary-theory/vol-01/Vol.1%2CNo.1%2C1-30%2CL.%20Van%20Valen%2C%20A%20new%20evolutionary%20law..pdf |journal=Evolutionary Theory |volume=1 |pages=1–30 |issn=0093-4755 |access-date=24 December 2014 |archive-url=https://web.archive.org/web/20141222094258/https://dl.dropboxusercontent.com/u/18310184/evolutionary-theory/vol-01/Vol.1%2CNo.1%2C1-30%2CL.%20Van%20Valen%2C%20A%20new%20evolutionary%20law..pdf |archive-date=22 December 2014}}</ref><ref name="parasite">{{cite journal |last1=Hamilton |first1=W. D. |author-link1=W. D. Hamilton |last2=Axelrod |first2=Robert |author-link2=Robert Axelrod |last3=Tanese |first3=Reiko |date=1 May 1990 |title=Sexual reproduction as an adaptation to resist parasites (a review) |journal=PNAS |volume=87 |issue=9 |pages=3566–3573 |bibcode=1990PNAS...87.3566H |doi=10.1073/pnas.87.9.3566 |issn=0027-8424 |pmid=2185476 |pmc=53943|doi-access=free }}</ref><ref name="Birdsell">{{harvnb|Birdsell|Wills|2003|pp=113–117}}</ref> Another hypothesis is that sexual reproduction is primarily an adaptation for promoting accurate recombinational repair of damage in germline DNA, and that increased diversity is a byproduct of this process that may sometimes be adaptively beneficial.<ref>Bernstein H, Byerly HC, Hopf FA, Michod RE. Genetic damage, mutation, and the evolution of sex. Science. 1985 Sep 20;229(4719):1277–81. {{doi|10.1126/science.3898363}}. PMID 3898363</ref><ref>Bernstein H, Hopf FA, Michod RE. The molecular basis of the evolution of sex. Adv Genet. 1987;24:323-70. {{doi|10.1016/s0065-2660(08)60012-7}}. PMID 3324702</ref> === Gene flow === {{further|Gene flow}} Gene flow is the exchange of genes between populations and between species.<ref name="Morjan C, Rieseberg L 2004 1341–56">{{cite journal |last1=Morjan |first1=Carrie L. |last2=Rieseberg |first2=Loren H. |author-link2=Loren H. Rieseberg |date=June 2004 |title=How species evolve collectively: implications of gene flow and selection for the spread of advantageous alleles |journal=[[Molecular Ecology]] |volume=13 |issue=6 |pages=1341–1356 |pmid=15140081 |doi=10.1111/j.1365-294X.2004.02164.x |issn=0962-1083 |pmc=2600545|bibcode=2004MolEc..13.1341M }}</ref> It can therefore be a source of variation that is new to a population or to a species. Gene flow can be caused by the movement of individuals between separate populations of organisms, as might be caused by the movement of mice between inland and coastal populations, or the movement of [[pollen]] between heavy-metal-tolerant and heavy-metal-sensitive populations of grasses. Gene transfer between species includes the formation of [[Hybrid (biology)|hybrid]] organisms and [[horizontal gene transfer]]. Horizontal gene transfer is the transfer of genetic material from one organism to another organism that is not its offspring; this is most common among bacteria.<ref>{{cite journal |last1=Boucher |first1=Yan |last2=Douady |first2=Christophe J. |last3=Papke |first3=R. Thane |last4=Walsh |first4=David A. |last5=Boudreau |first5=Mary Ellen R. |last6=Nesbo |first6=Camilla L. |last7=Case |first7=Rebecca J. |last8=Doolittle |first8=W. Ford |date=December 2003 |title=Lateral gene transfer and the origins of prokaryotic groups |journal=[[Annual Review of Genetics]] |volume=37 |pages=283–328 |doi=10.1146/annurev.genet.37.050503.084247 |issn=0066-4197 |pmid=14616063 |display-authors=3}}</ref> In medicine, this contributes to the spread of [[antibiotic resistance]], as when one bacteria acquires resistance genes it can rapidly transfer them to other species.<ref name="GeneticEvolution">{{cite journal |last=Walsh |first=Timothy R. |date=October 2006 |title=Combinatorial genetic evolution of multiresistance |journal=[[Current Opinion (Elsevier)|Current Opinion in Microbiology]] |volume=9 |issue=5 |pages=476–482 |doi=10.1016/j.mib.2006.08.009 |issn=1369-5274 |pmid=16942901}}</ref> Horizontal transfer of genes from bacteria to eukaryotes such as the yeast ''[[Saccharomyces cerevisiae]]'' and the adzuki bean weevil ''[[Callosobruchus chinensis]]'' has occurred.<ref>{{cite journal |last1=Kondo |first1=Natsuko |last2=Nikoh |first2=Naruo |last3=Ijichi |first3=Nobuyuki |last4=Shimada |first4=Masakazu |last5=Fukatsu |first5=Takema |date=29 October 2002 |title=Genome fragment of ''Wolbachia'' endosymbiont transferred to X chromosome of host insect |journal=PNAS |volume=99 |issue=22 |pages=14280–14285 |bibcode=2002PNAS...9914280K |doi=10.1073/pnas.222228199 |issn=0027-8424 |pmc=137875 |pmid=12386340 |display-authors=3|doi-access=free }}</ref><ref>{{cite journal |last=Sprague | first=George F. Jr. |date=December 1991 |title=Genetic exchange between kingdoms |journal=Current Opinion in Genetics & Development |volume=1 |issue=4 |pages=530–533 |doi=10.1016/S0959-437X(05)80203-5 |issn=0959-437X |pmid=1822285}}</ref> An example of larger-scale transfers are the eukaryotic [[Bdelloidea|bdelloid rotifers]], which have received a range of genes from bacteria, fungi and plants.<ref>{{cite journal |last1=Gladyshev |first1=Eugene A. |last2=Meselson |first2=Matthew |author-link2=Matthew Meselson |last3=Arkhipova |first3=Irina R. |s2cid=11862013 |date=30 May 2008 |title=Massive Horizontal Gene Transfer in Bdelloid Rotifers |journal=[[Science (journal)|Science]] |volume=320 |issue=5880 |pages=1210–1213 |bibcode=2008Sci...320.1210G |doi=10.1126/science.1156407 |issn=0036-8075 |pmid=18511688 |url=http://nrs.harvard.edu/urn-3:HUL.InstRepos:3120157 |access-date=30 July 2022 |archive-date=30 July 2022 |archive-url=https://web.archive.org/web/20220730090619/https://dash.harvard.edu/handle/1/3120157 |url-status=live }}</ref> Viruses can also carry DNA between organisms, allowing transfer of genes even across [[Domain (biology)|biological domains]].<ref>{{cite journal |last1=Baldo |first1=Angela M. |last2=McClure |first2=Marcella A. |date=September 1999 |title=Evolution and Horizontal Transfer of dUTPase-Encoding Genes in Viruses and Their Hosts |journal=[[Journal of Virology]] |volume=73 |issue=9 |pages=7710–7721 |issn=0022-538X |pmc=104298 |pmid=10438861|doi=10.1128/JVI.73.9.7710-7721.1999 }}</ref> Large-scale gene transfer has also occurred between the ancestors of [[eukaryotic cell]]s and bacteria, during the acquisition of [[chloroplast]]s and [[Mitochondrion|mitochondria]]. It is possible that eukaryotes themselves originated from horizontal gene transfers between bacteria and [[archaea]].<ref>{{cite journal |last1=Rivera |first1=Maria C. |last2=Lake |first2=James A. |author-link2=James A. Lake |date=9 September 2004 |title=The ring of life provides evidence for a genome fusion origin of eukaryotes |url=https://archive.org/details/sim_nature-uk_2004-09-09_431_7005/page/152 |journal=Nature |volume=431 |issue=7005 |pages=152–155 |bibcode=2004Natur.431..152R |doi=10.1038/nature02848 |issn=0028-0836 |pmid=15356622|s2cid=4349149 }}</ref> === Epigenetics === {{further|Epigenetics}} Some heritable changes cannot be explained by changes to the sequence of [[nucleotide]]s in the DNA. These phenomena are classed as epigenetic inheritance systems.<ref name="Jablonka09">{{cite journal |last1=Jablonka |first1=Eva |last2=Raz |first2=Gal |date=June 2009 |title=Transgenerational Epigenetic Inheritance: Prevalence, Mechanisms, and Implications for the Study of Heredity and Evolution |journal=The Quarterly Review of Biology |volume=84 |issue=2 |pages=131–176 |doi=10.1086/598822 |issn=0033-5770 |pmid=19606595 |url=http://compgen.unc.edu/wiki/images/d/df/JablonkaQtrRevBio2009.pdf |citeseerx=10.1.1.617.6333 |s2cid=7233550 |access-date=30 July 2022 |archive-date=15 July 2011 |archive-url=https://web.archive.org/web/20110715111243/http://compgen.unc.edu/wiki/images/d/df/JablonkaQtrRevBio2009.pdf |url-status=live }}</ref> [[DNA methylation]] marking [[chromatin]], self-sustaining metabolic loops, gene silencing by [[RNA interference]] and the three-dimensional [[Protein structure|conformation]] of [[protein]]s (such as [[prion]]s) are areas where epigenetic inheritance systems have been discovered at the organismic level.<ref name="Bossdorf10">{{cite journal |last1=Bossdorf |first1=Oliver |last2=Arcuri |first2=Davide |last3=Richards |first3=Christina L. |last4=Pigliucci |first4=Massimo |s2cid=15763479 |author-link4=Massimo Pigliucci |date=May 2010 |title=Experimental alteration of DNA methylation affects the phenotypic plasticity of ecologically relevant traits in ''Arabidopsis thaliana'' |journal=Evolutionary Ecology |volume=24 |issue=3 |pages=541–553 |doi=10.1007/s10682-010-9372-7 |bibcode=2010EvEco..24..541B |issn=0269-7653 |url=http://doc.rero.ch/record/318722/files/10682_2010_Article_9372.pdf |access-date=30 July 2022 |archive-date=5 June 2022 |archive-url=https://web.archive.org/web/20220605101316/http://doc.rero.ch/record/318722/files/10682_2010_Article_9372.pdf |url-status=live }}</ref> Developmental biologists suggest that complex interactions in [[gene regulatory network|genetic networks]] and communication among cells can lead to heritable variations that may underlay some of the mechanics in [[developmental plasticity]] and [[Canalisation (genetics)|canalisation]].<ref name="Jablonka02">{{cite journal |last1=Jablonka |first1=Eva |last2=Lamb |first2=Marion J. |date=December 2002 |title=The Changing Concept of Epigenetics |journal=[[Annals of the New York Academy of Sciences]] |volume=981 |issue=1 |pages=82–96 |bibcode=2002NYASA.981...82J |doi=10.1111/j.1749-6632.2002.tb04913.x |issn=0077-8923 |pmid=12547675|s2cid=12561900 }}</ref> Heritability may also occur at even larger scales. For example, ecological inheritance through the process of [[niche construction]] is defined by the regular and repeated activities of organisms in their environment. This generates a legacy of effects that modify and feed back into the selection regime of subsequent generations.<ref name="Laland06">{{cite journal |last1=Laland |first1=Kevin N. |last2=Sterelny |first2=Kim |author-link2=Kim Sterelny |date=September 2006 |title=Perspective: Seven Reasons (Not) to Neglect Niche Construction |journal=[[Evolution (journal)|Evolution]] |volume=60 |issue=9 |pages=1751–1762 |doi=10.1111/j.0014-3820.2006.tb00520.x |pmid=17089961 |s2cid=22997236 |issn=0014-3820|doi-access=free }}</ref> Other examples of heritability in evolution that are not under the direct control of genes include the inheritance of cultural traits and [[symbiogenesis]].<ref name="Chapman98">{{cite journal|last1=Chapman |first1=Michael J. |last2=Margulis |first2=Lynn |author-link2=Lynn Margulis |date=December 1998 |title=Morphogenesis by symbiogenesis |url=http://www.im.microbios.org/04december98/14%20Chapman.pdf |journal=[[International Microbiology]] |volume=1 |issue=4 |pages=319–326 |issn=1139-6709 |pmid=10943381 |access-date=9 December 2014 |archive-url=https://web.archive.org/web/20140823062546/http://www.im.microbios.org/04december98/14%20Chapman.pdf |archive-date=23 August 2014}}</ref><ref name="Wilson07">{{cite journal |last1=Wilson |first1=David Sloan |author-link1=David Sloan Wilson |last2=Wilson |first2=Edward O. |author-link2=E. O. Wilson |date=December 2007 |title=Rethinking the Theoretical Foundation of Sociobiology |url=http://evolution.binghamton.edu/dswilson/wp-content/uploads/2010/01/Rethinking-sociobiology.pdf |journal=The Quarterly Review of Biology |volume=82 |issue=4 |pages=327–348 |doi=10.1086/522809 |issn=0033-5770 |pmid=18217526 |s2cid=37774648 |archive-url=https://web.archive.org/web/20110511235639/http://evolution.binghamton.edu/dswilson/wp-content/uploads/2010/01/Rethinking-sociobiology.pdf |archive-date=11 May 2011}}</ref> Summary: Please note that all contributions to Christianpedia may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here. You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Christianpedia:Copyrights for details). Do not submit copyrighted work without permission! Cancel Editing help (opens in new window) Discuss this page