Question

为什么说基因突变的结果是产生等位基因?

Answer 1

等位基因是一个与群体有关的概念，而基因的突变多涉及个体。如果个体的突变能够在群体中固定下来，并且与某种表型有关联，那就会被认定为等位基因。因此，一部分基因突变的结果是产生等位基因的。试想，一个个体发生某个基因突变，并导致个体的死亡，该突变不会在群体中存在，也就不称之为等位基因了。因此这个论断还是需要修正。

Reference:
An allele (pronounced /ˈæliːl/ (UK), /əˈliːl/ (US); from the Greek αλληλος allelos, meaning each other) is one of a series of different forms of a genetic locus.[1] The word is a short form of allelomorph ('other form'), which was used in the early days of genetics to describe variant forms of a gene detected as different phenotypes. Alleles are now understood to be alternative DNA sequences at the same physical locus, which may or may not result in different phenotypic traits. In any particular diploid organism, with two copies of each chromosome, the genotype for each gene comprises the pair of alleles present at that locus, which are the same in homozygotes and different in heterozygotes. A population or species of organisms typically includes multiple alleles at each locus among various individuals. Allelic variation at a locus is measurable as the number of alleles (polymorphism) present, or the proportion of heterozygotes (heterozygosity) in the population.
For example, at the gene locus for ABO blood type proteins in humans [1], classical genetics recognizes three alleles, IA, IB, and IO, that determines compatibility of blood transfusions. Any individual has one of six possible genotypes (AA, AO, BB, BO, AB, and OO) that produce one of four possible phenotypes: "A" (produced by AA homozygous and AO heterozygous genotypes), "B" (produced by BB homozygous and BO heterozygous genotypes), "AB" heterozygotes, and "O" homozygotes. It is now appreciated that each of the A, B, and O alleles is actually a class of multiple alleles with different DNA sequences that produce proteins with identical properties: more than 70 alleles are known at the ABO locus.[2] An individual with "Type A" blood may be a AO heterozygote, an AA homozygote, or an A'A heterozygote with two different 'A' alleles.

Answer 2

简单地说，基因突变后形成一个新的基因，并且还在原来的位置，而同源染色体上相同位置的基因就是等位基因。

Answer 3

本来两条染色体上面是同一个基因
现在有一条染色体上的一个基因变了，但是这两个基因还是控制同一个东西的（比如控制单眼皮和双眼皮）
只是表现性状不一样了
这两个基因本来就是同源的
现在虽然表现不一样了，但是说白了还是同一种基因，就是等位基因

Answer 4

当然了，要不然不就基因错位了

Answer 5

基因突变一般是指在基因尺度上的DNA序列的变化，用来区分染色体突变。
一般基因突变会包括少数碱基对的突变，或者一段或几段序列的插入或者删除，而这些突变之后，原有基因的绝大部分序列并没有变化，因此原先在一对染色体上的配对基因仍然能够配对和同源重组。
我们一般上把能否发生同源重组，即在染色体水平上，两个基因所在的染色体区域能否配对作为是否是等位基因的标准。因此基因突变以后，产生了新的基因，该基因与原基因所在的相对另一条染色体上的基因仍能配对，互称等位基因。