人口和基因集合 - 高级

With close to 90,000 birds in this colony, how many alleles is that?
::这个殖民地里有近90,000只鸟 有多少灵精?

Shown is a colony of Northern Gannets on Bonaventure Island, the home of the largest Northern Gannet in the world. It is a protected reserve and is located near Perce, Quebec. A gene pool contains the of the entire population.
::Shown是世界最大的北方甘蔗园所在地,Bonaventur Island上的北方甘蔗园殖民地,是一个受保护的保护区,位于魁北克Perce附近,一个基因库包含全部人口。

Populations and Gene Pools
::人口和基因库

Individuals do not evolve. may affect an individual’s chance to survive and reproduce, but it cannot change the individual’s genes . However, a population – a group of organisms of a single in a certain area – evolves when natural selection imposes differential survival on individuals within it. Population genetics studies populations at the level of genes and alleles in order to discover how evolution works.
::个人不会进化。 个人可能影响到个人生存和繁殖的机会,但不能改变个人的基因。 然而,当自然选择迫使个人生存差异时,人口 — — 某个地区单一生物群 — — 就会演变。 人口基因学研究基因和异系层次的人口,以便发现进化是如何运作的。

If we consider all the alleles of all the genes of all the individuals within a population, we have defined the gene pool for that population. Gene pools contain all the – the raw material for natural selection – within a population. The gene pool for a rabbit population, for example, includes alleles which determine coat color, ear size, whisker length, tail shape, and many other traits ( Table ). If a population geneticist wants to focus on the variation in an individual gene, she/he may look at the gene pool of all the alleles for that gene alone.
::如果我们考虑到人口中所有个人基因的所有所有基因的方位,我们已经为该人群确定了基因库。 基因库包含人口中所有 — — 自然选择的原材料 — — 的基因库。 比如,兔子群的基因库包括决定大衣颜色、耳朵大小、长须、尾部形状和许多其他特征的方位(表 ) 。 如果人口基因学家想要关注个体基因的变化,她/他可以单独查看所有异端基因的基因库。

Consider a population of 100 rabbits, including 10 albinos and 90 brown rabbits. The proportion of each phenotype is a measure of variation in this population, but it does not show the true genetic diversity . The gene pool does. Two populations of 10 white and 90 brown rabbits – with identical phenotypic diversity - could differ genetically, because brown rabbits could be either homozygous or heterozygous.
::以100只兔子为例,包括10只白化病和90只棕色兔子。 每只苯型兔子的比例是这一人群中一个差异的尺度,但它并没有显示真正的遗传多样性。 基因库确实存在。 两只10只白色兔子和90只棕色兔子 — — 与黄色兔子一样 — — 在基因上可能存在差异,因为棕色兔子可以是同质虫,也可以是异体虫。

Rabbits, like humans, are diploid . Therefore, each population’s gene pool for coat color contains 200 alleles. The 10 albinos in each population contribute a total of 20 b alleles to each gene pool. However, if population #1 has 40 heterozygotes and population #2 just 20, then their gene pools differ significantly.
::兔子和人类一样,都是低脂的。 因此,每个人口的涂层基因库中含有200个异色。 每个人口的10个白化病患者在每个基因库中总共贡献了20个异性病患者。 但是,如果1号人口有40个异性螺旋菌和2号仅20个,那么他们的基因库就大相径庭。

In population #1, 50 homozygous dominant individuals contribute 100 B alleles, and the 40 heterozygotes contribute 40 more. The heterozygotes also contribute 40 albino b alleles. Thus, population #1 contains a total of 140 B alleles and 60 b alleles.
::在1号人群中,50个同种人占优势的个人占了100个B方位,40个异种人占了40个以上。异种人占了40个。异种人占优势的个人占了40个。因此,1号人口占了140个B方位和60个b方位。

Population #2, on the other hand, has 70 homozygous dominant rabbits, which add 140 B alleles to the 20 from the heterozygotes – a total of 160 B alleles. Only 40 b alleles are present in the gene pool, so genetic diversity is lower. The use of gene pools allows population geneticists to see variation and the influence of natural selection in detail.
::另一方面,2号人口有70个同种人占优势的兔子,其中异体人种的20个兔子中增加了140个蛋白,共增加了160个蛋白。 基因库中只有40个蛋白,基因多样性因此较低。 基因库的使用使得人口基因学家们能够详细看到自然选择的变异和影响。

A single gene may show significantly less genetic variation than the variation within the whole genome of a population. It is even possible, though maybe unlikely, for some small populations to have no variation in the sequence of any one particular gene. Thus it is the complete gene pool which contains the variation necessary for evolution.
::单一基因的基因变异可能比整个人口基因组的变异要小得多。 一些小的基因组在任何特定基因序列上可能没有变化,尽管可能不太可能。 因此,整个基因库包含进化所需的变异。

Table of Phenotypes and Genotypes in Two Rabbit Populations

Phenotypes	Number of each phenotype	Genotypes	Number of each genotype	Alleles contributed to gene pool	Total gene pool
播放段落 Rabbit Population #1 ::1号兔子人口	$\begin{array}{r}90\end{array}$ $\begin{array}{r}brown\end{array}$	$\begin{array}{r}BB\end{array}$	$\begin{array}{r}50\end{array}$	$\begin{array}{r}100B\end{array}$	$\begin{array}{r}140B\end{array}$
		$\begin{array}{r}Bb\end{array}$	$\begin{array}{r}40\end{array}$	$\begin{array}{r}40B+40b\end{array}$	$\begin{array}{r}\end{array}$
	$\begin{array}{r}10\end{array}$ $\begin{array}{r}albino\end{array}$	$\begin{array}{r}bb\end{array}$	$\begin{array}{r}10\end{array}$	$\begin{array}{r}20b\end{array}$	$\begin{array}{r}60b\end{array}$
播放段落 Rabbit Population #2 ::2号兔子人口	$\begin{array}{r}90\end{array}$ $\begin{array}{r}brown\end{array}$	$\begin{array}{r}BB\end{array}$	$\begin{array}{r}70\end{array}$	$\begin{array}{r}140B\end{array}$	$\begin{array}{r}160B\end{array}$
		$\begin{array}{r}Bb\end{array}$	$\begin{array}{r}20\end{array}$	$\begin{array}{r}20B+20b\end{array}$	$\begin{array}{r}\end{array}$
	$\begin{array}{r}10\end{array}$ $\begin{array}{r}albino\end{array}$	$\begin{array}{r}bb\end{array}$	$\begin{array}{r}10\end{array}$	$\begin{array}{r}20b\end{array}$	$\begin{array}{r}40b\end{array}$

As saw, populations are the units of evolution. As showed but Darwin could not have seen, heritable units, which we now know as alleles, determine the amount of variation within a population. A measure of this variation is the population’s gene pool. Once again, individuals cannot evolve, but it is the individual organism that adapts to its environment. It is the gradual accumulation of a series of adaptations - through genetic change - in a lineage from the population that is evolution.
::正如人们所看到的,人口是进化的单位。 但达尔文不可能看到,我们目前所认识的异系群决定了人口内部的变异程度。 这种变异的一个尺度是人口的基因库。 再一次,个人不能进化,但适应环境的是个体有机体。 这是通过基因变化逐渐积累的一系列适应(通过基因变化)在与人口相邻的分系中的演化过程。

Summary
::摘要

播放段落
• Individuals experience natural selection, but not the genetic changes of evolution.
  ::个人经历自然选择,但不经历进化的基因变化。
播放段落
• Populations evolve through genetic change.
  ::人口通过基因变化而演变。
播放段落
• A population’s gene pool includes all the alleles of all the genes of all the individuals within it.
  ::人口基因库包括人口基因库内所有个人的所有基因的异灵。
播放段落
• A gene pool for a single gene includes all the alleles of that gene present in all individuals.
  ::单一基因的基因库包括所有个体中存在的该基因的所有灵长类。
播放段落
• Analysis of a gene pool can reveal variation which is not visible in phenotypes.
  ::对基因库的分析可以揭示在苯型中无法见的变异。

Review
::回顾

播放段落
1. Explain why populations, but not individuals, can evolve.
   ::解释为什么人口而不是个人可以演变。
播放段落
2. Distinguish between a population’s gene pool and a gene pool for a single gene.
   ::区分人口的基因库和单一基因的基因库。