The law of biological variation: offspring like parents, offspring are not parents

Author(s)

Abstract
At present, there are 5 million to 30 million species of organisms on the Earth, how did so many kinds of organisms come into being? What is the pattern of their variation? So far, there is no satisfactory theory to explain it. Since Watson and Crick proposed the double helix structure model of genetic material DNA in 1953, human understanding of the causes of biological evolution has entered the era of molecular genetics. Over the past 70 years, human understanding of genetic phenomena has increased a lot, among which two points are very noteworthy. (1)The genome of organisms will undergo mutations and recombination in the course of generations. Mutation and recombination are the key processes that cause genome changes. (2) In the continuation of generations, regardless of sexual reproduction or asexual reproduction, heterozygous effects will occur. Heterozygous effects include: variation of DNA nucleotide sequence; Differences in mRNA expression (differences in gene expression rate and gene expression amount); Differences in protein structure; DNA methylation in certain regions; Multiplication of nucleotide sequences, entire genomes, or chromosomes; Heritable gene expression changes that are not caused by changes in DNA sequence, etc.The variation characteristics of organisms in the succession of generations show microdegree, gradualism, pluralism and randomness. Micro and progressive means that the variation of each genome is micro and progressive, the so-called "offspring like parents, offspring are not parents"; The diversity of variation refers to the variation of the nucleotide sequence in the offspring, which does not occur in one place, but in multiple places compared with the parent, which includes both nucleotide sequence variation and epigenetic phenomenon of non-nucleotide sequence change. The randomness of biological variation means that mutation and recombination are random, non-directional, and not affected by the environment. Beneficial mutations get positive selection and harmful mutations get negative selection. This is the main genetic cause of biodiversity on Earth. Due to the different length of time between generations of various organisms, some change faster, the reproductive cycle is only a few hours, a few days (such as some viruses, bacteria), and some change slower, to several years, even hundreds of years, thousands of years. The result of evolution is that some prosper, some become blind, some become new species, and some become dead.

Keywords
biodiversity, gene recombination and mutation, heterozygous effect

Cite this paper
Linyun Wang, The law of biological variation: offspring like parents, offspring are not parents , SCIREA Journal of Agriculture. Volume 8, Issue 3, June 2023 | PP. 137-151. 10.54647/agriculture210392

References