Inheritance (遺傳, English: heredity) is the transmission of genetic traits from parents to offspring.
A new generation of offspring inherits hereditary traits from their parents. Genetic traits include things like the color of the iris, skin, and hair, traits such as blood type, and genetic diseases such as hemophilia. DNA contains the genetic information of living things. Prokaryotes do not have a separate cell nucleus, so DNA is suspended in the cytoplasm, whereas eukaryotes have DNA in chromosomes within the cell nucleus. In the case of viruses, RNA sometimes takes the place of DNA. Organisms pass on their genetic information to their offspring by replicating DNA during cell division. Reproduction, in which an organism reproduces the next generation, includes asexual reproduction, which does not discriminate between sexes, and sexual reproduction, in which males and females are distinguished. In asexual reproduction, genetic traits are transmitted through division of somatic cells, and in sexual reproduction, sperm and egg produced by meiosis of male and female are fertilized to form a new individual. After all, heredity is the transmission of hereditary traits through reproduction. In the process of DNA replication, mutations that rarely occur in children have different genes from their parents' genes. Mutations are responsible for the development and evolution of alleles.
All genetic phenomena are based on the transmission of genetic traits through DNA replication. In asexual reproduction, which is reproduction in which genetic traits are transmitted through mitosis, one's own DNA is copied and passed on to offspring. However, in sexual reproduction, a more complicated process is made because gametes are created through meiosis after alleles are mixed through genetic recombination.
Muller's Jagged Hypothesis is a theory that explains the benefits of sexual reproduction evolving to pass genetic traits to offspring through such a complex process. In other words, if asexual reproduction continues, harmful mutations may accumulate and eventually adversely affect the survival of the species.
Expression of Traits
Genetic traits transmitted by genes do not determine everything in biogenesis. Expression traits, which are characteristics that appear during actual development and growth of living things, are affected by the characteristics of the genetic trait itself and the environment.
Dominance and Recession
The dominant and recessive characteristics established in Mendel's laws of inheritance are representative due to the characteristics of the genetic trait itself. When a dominant gene and a recessive gene are paired, only the dominant factor is expressed as an expression characteristic, and the recessive factor does not appear. However, unexpressed recessive factors are also passed on to the next generation. In dominance and recessiveness, as in Mendel's law of inheritance, there are cases where only one genetic factor is placed in one locus and obeys the law of independence, but it is also possible to have a quantitative trait position in which multiple genetic factors selectively enter one locus. have.
A representative quantitative trait expression of dominance and recessiveness according to location is human blood type. In the ABO blood group, factor A and factor B selectively enter the same locus and are dominant, whereas factor O is recessive. As a result, as shown in the table on the left, type O blood type is expressed only when the type O factor is inherited from both parents. Otherwise, both AA and AO are type A, BB and BO are both type B, and AB is type AB. The table on the left shows only the superiority and inferiority of blood type expression, not the actual blood type in the distribution of the population. Blood types in the actual population distribution may be biased toward a specific blood type in each community. For example, if you are not of mixed race �