What Is a Gene Library?

A gene pool is the sum of all genes of all individuals in a population. Sexual reproduction supports a unique model of gene bank construction and operation, and meiosis is repaired and programmed mutations (such as replication errors, deletions, insertions, duplications, etc., which are relatively mild compared with radiation mutagenesis) It can increase the diversity of genes in a population and the polymorphism of alleles, and store them dispersedly in the population (the larger the population size, the greater the potential for accommodation), this is an efficient and relatively safe species gene bank amplification the way.

1. In a certain area, all members of a species constitute a population. The main characteristic of the population is that the male and female individuals in the population can pass

Gene bank For diploid organisms, the gene bank of a population of n individuals consists of 2n haploid genomes. Therefore, in a population gene bank with n individuals, for each locus, there are 2n genes each, and there are n pairs of homologous chromosomes in total. The exceptions are sex chromosomes and sex-linked genes, which are present in only a single dose in individuals with heterotypic gametes. The phenotype of an organism can be directly observed, but the genotype and genes cannot be directly observed. The variation in the gene bank can be determined by the frequency of the genotype or

Gene bank evolution

Changes in the gene frequency of a population or a species are called micro-evolution, and evolution at a level above a population is called macro-evolution.

Gene bank species formation mechanism

The genetic system and the genome itself are considered to be a relationship as a whole, the center of adaptation and various adjustments: the genetic unit is not so much the genome itself, but rather the "gene bank" or genomic aggregation of a "population"; In turn, the gene bank must adapt and integrate, and become the source of all regulation and constant rebalancing. Therefore, it constitutes (or as some famous theorists say) an intermediate level of integration between individuals and species (Piaget 1989). People have a fairly accurate understanding of the overall behavior of genes during sexual reproduction, and they are also potentially aware of the adaptive significance of population gene banks as a whole. Some scholars have explained the formation mechanism of species from the perspective of gene banks:

1) The gene banks of most eukaryotic species (the genes of all individuals and their combinations and associations) are fluidly maintained in the entire population through sexual reproduction (meiosis, fusion of bisexual gametes). The relationship between genetic diversity and environmental adaptability of species is contained in the gene pool of the population.

2) Sexual reproduction is not intentional in order to create more genetic variation (this is fundamentally different from traditional concepts), it is just an operation method to implement the elongation process of eukaryotic species. Therefore, the genome of any individual is one of the random combinations from the population gene bank. The diversity of the gene bank fundamentally determines the diversity of the individual genetic combination (and therefore the phenotype).

3) In this way, the entire genome of any sexually reproduced individual will not be immortal, and it will inevitably be fragmented or fragmented with repeated genetic reorganization during the passage of meiosis, and disappear in the vast Ruyan Population gene bank.

4) In the actual living environment, due to survival competition, isolation or the environment (including biotic or abiotic), the gene pool of a species may expand, some may shrink, and some may shrink. Division, which in turn complicates, degrades, or differentiates the species.

5) In the sexual reproduction mode, the gene bank (and therefore the phenotype) of any prosperous species inevitably (though very slowly) tends to have greater variability and diversity (this is easily caused by meiosis Due to genetic recombination and mutation characteristics), but it also increases the chance of unsuccessful mating between individuals (for example, the incidence of infertility in humans is more than 5%). Therefore, natural selection and evolution shape or determine the dynamics and balance between the genetic (phenotypic) diversity, mating success rate, and environmental adaptability of these species.

6) The diversity of the gene bank of any particular species cannot be infinitely expanded. Under similar conditions, the higher the genetic diversity, the greater the probability that the gene bank will divide. The gene bank division of the seed is often highly overlapping, with only minimal alienation (for example, chimpanzees and human genomes are up to 98.8% similar). In this way, sexual reproduction promotes the continuous birth of new species through the cumulative effect of time, so that the species of eukaryotes on the planet show a never-ending momentum of differentiation. ^[2]

In eukaryotes, the collective preservation mechanism of species-based gene banks is consistent with the collective survival and extension patterns of species. The existence of extensive genetic polymorphisms is a strong evidence for the collective preservation of gene banks of sexually reproductive species. In 1966, Levantin and Habi collaborated on the study of protein variation using electrophoresis technology and found that in a population of fruit flies, about 30% of the loci are polymorphic (with different alleles). Subsequent research found that the genetic polymorphisms of general organisms are around 10-20% (Fang Zhouzi 2005). ^[3]

Gene Bank Hybridization and Differentiation

The greater the differences in gene pools (or, in general, the more distant the genetic relationships between species), the less likely it is that species will successfully cross. However, although some populations have been isolated for a long time, if the gene bank is not differentiated, they may still be able to mate successfully. Some people believe that there is a selfing or inbreeding decline, they will logically believe that there is a so-called "hybrid advantage". The long-established agronomic breeding is just to find and use some so-called "beneficial" advantage traits for humans. But this may not always be the case for hybrids. Some (traits) advantages, some may be disadvantaged, and some may be neutral, depending on the genomic (and therefore physiological) differences, integration, and assimilation between the two species. ^[2]

It is precisely because of this ecological genetics nature of sexual reproduction that the gene bank of any species cannot remain unchanged, so any species will not continue forever, it will either be destroyed by the environment or it will disappear from its own Change (species differentiation), and when this change reaches the level that can form reproductive isolation (whether in the same domain or foreign), it will lead to species differentiation ^[2] . As Meyer (2009) points out, the less gene flow between populations, the faster the seeding event, which is true for all living things ^[4] .