RESUMO
The Synthetic Theory of Evolution is the most unifying theory of life science. This theory has dominated scientific thought in explaining the mechanisms involved in speciation. However, there are some omissions that have delayed the understanding of some aspects of the mechanisms of organic evolution, principally: 1) the bridge between somatic and germinal cells, especially in some phylum of invertebrates and vertebrates; 2) horizontal genetic transferences and the importance of viruses in host adaptation and evolution; 3) the role of non-coding DNA and non-transcriptional genes; 4) homeotic evolution and the limitations of gradual evolution; and 5) excessive emphasis on extrinsic barriers to animal speciation. This paper reviews each of these topics in an effort to contribute to a better comprehension of organic evolution. Molecular findings suggest the need for a new evolutionary synthesis.
Assuntos
Evolução Biológica , Epigênese Genética/genética , Genética Populacional , Invertebrados/genética , Seleção Genética/genética , Vertebrados/genética , Animais , Interações Hospedeiro-Patógeno/genética , Humanos , Filogenia , Vírus/genéticaRESUMO
The Synthetic Theory of Evolution is the most unifying theory of life science. This theory has dominated scientific thought in explaining the mechanisms involved in speciation. However, there are some omissions that have delayed the understanding of some aspects of the mechanisms of organic evolution, principally: 1) the bridge between somatic and germinal cells, especially in some phylum of invertebrates and vertebrates; 2) horizontal genetic transferences and the importance of viruses in host adaptation and evolution; 3) the role of non-coding DNA and non-transcriptional genes; 4) homeotic evolution and the limitations of gradual evolution; and 5) excessive emphasis on extrinsic barriers to animal speciation. This paper reviews each of these topics in an effort to contribute to a better comprehension of organic evolution. Molecular findings suggest the need for a new evolutionary synthesis.
Assuntos
Humanos , Animais , Evolução Biológica , Epigênese Genética/genética , Genética Populacional , Invertebrados/genética , Seleção Genética/genética , Vertebrados/genética , Interações Hospedeiro-Patógeno/genética , Filogenia , Vírus/genéticaRESUMO
Within the nuclear eukaryotic genome there are two different information areas. One of these zones corresponds to coding DNA in which "structural genes" or "lower genes" can be found. On the other hand, disperse in the genome, there is the non-coding DNA, where redundant DNA can be found. In the latter area there are non-transcriptional genes or "higher genes" which arose with eukaryotic organisms as a result of coevolution. Viruses could have had an important role as natural vectors in the genomic evolution.
Assuntos
Genes/genética , Filogenia , Cromossomos/genética , Evolução Molecular , Heterocromatina/genética , Processos de Determinação SexualRESUMO
The concept of heredity arose when the ancient philosophers and scientists felt the need to explain the variation and organic evolution phenomena. The ideas about inheritance developed before Mendel were significant in the construction of the Mendelian concept of gene. From Mendelian hereditary principles to molecular genetics there have been many different concepts and also many definitions of gene. In the first corpuscular concept of gene, mutation was quite crucial to explain the different alternative genotype and phenotype expression in the progeny. From the rediscovery of Mendelian Principles to 1961, Morgan's idea that a gene is not divisible by recombination prevailed. Nevertheless it was later demonstrated that there are different units of recombination and mutation within the gene, and in a determinate gene different "functional units" can exist. In 1977, surprisingly, Sharp and Roberts found out that genes are fragmented into "exons" and "introns". At present time, with the discovery of iRNA, non coding RNA, importance of introns, transposable elements, pseudogenes, endogenous viral DNA, repeated DNA, superposed genes, non-transcriptional genes and epigenesis, ancient questions return: what is a gene? where is the program? what is the true role of mutations in the organic evolution?