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  • 继承遗传遗传

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    Like Father, Like Son
    ::像父亲一样,像儿子一样

    This father-son duo are serving in the army together. The shape of their faces and their facial features look very similar. If you saw them together, you might well guess that they are father and son. People have long known that the characteristics of living things are similar between  parents and their offspring. However, it wasn’t until the of Gregor that scientists understood how  those traits are inherited.
    ::父亲和儿子在军队服役。 他们的脸容和面部特征看起来非常相似。 如果你看到他们在一起,你很可能猜到他们是父亲和儿子。 人们早就知道,父母和后代之间的生活特征是相似的。 然而,直到Gregor的科学家才知道这些特征是如何继承的。

    The Father of Genetics
    ::遗传之父

    Mendel did experiments with to show how traits such as seed shape and flower color are inherited. Based on his research, he developed his two well known laws of inheritance: the law of segregation and the law of independent assortment . When Mendel died in 1884, his work was still virtually unknown. In 1900, three other researchers working independently came to the same conclusions that Mendel had drawn almost half a century earlier. Only then was Mendel's work rediscovered.
    ::门德尔做了实验,以展示种子形状和花色等特征是如何继承的。根据他的研究,他制定了他的两个众所周知的继承法:隔离法和独立各种法。当曼德尔于1884年去世时,他的工作仍然几乎无人知晓。在1900年,另外三名独立工作的研究人员得出了与曼德尔近半个世纪前一样的结论。直到那时,门德尔的工作才重新被发现。

    Mendel knew nothing about genes , because they were discovered after his death. He did think, however, that some type of "factors" controlled traits, and that those "factors" were passed from parents to offspring. We now call these "factors" genes. of inheritance , now expressed in terms of genes,  form the basis of genetics , the science of heredity . For this reason, Mendel is often called the father of genetics.
    ::门德尔对基因一无所知,因为基因是他死后发现的。但是,他确实认为某种“因素”控制特性,这些“因素”是从父母传给后代的。我们现在将这些“因素”基因称为继承基因的“因素 ” 。 这些遗传基因现在以基因的形式表达,形成基因的基础,遗传科学。因此,门德尔常常被称为基因之父。

    The Language of Genetics
    ::遗传学语言

    Today, we know that traits of organisms are controlled by genes on . To talk about inheritance in terms of genes and chromosomes, you need to know the language of genetics. The terms below serve   as a good starting point. They are illustrated in the that follows.
    ::今天,我们知道生物的特性是由基因控制的。要讨论遗传基因和染色体方面的继承问题,你需要了解遗传学的语言。下面的术语是一个良好的起点。下面的语句说明了这些特征。

    • A gene is the part of a chromosome that contains the for a given . For example, in pea plants, a given gene might code for flower color.
      ::基因是染色体的一部分,含有给定的染色体。例如,在豆类植物中,给定的基因可能为花朵颜色编码。
    • The position of a given gene on a chromosome is called its  locus (plural, loci). A gene might be located near the center, or at one end or the other of a chromosome.
      ::染色体上特定基因的位置被称为其位置(多元、地方 ) 。 一种基因可能位于中心附近,或染色体的一端或另一端。
    • A given gene may have different normal versions, which are called . For example, in pea plants, there is a purple-flower allele (B) and a white-flower allele (b) for the flower-color gene. Different alleles account for much of the variation in the traits of organisms, including people.
      ::给定基因可能具有不同的正常版本,这些版本被称为 。 例如,在豆类植物中,花朵基因有紫花色(B)和白花花色(b),不同基因占生物特征(包括人)差异的很大一部分。
    • In sexually reproducing organisms, each individual has two copies of each type of chromosome. Paired chromosomes of the same type are called homologous chromosomes . They are about the same size and shape, and they have all the same genes at the same loci.
      ::在性再生生物中,每个人都有两种染色体的复制件。同类的同种染色体被称为同种染色体。它们大小和形状大致相同,同一地方的基因都相同。

    lesson content

    Chromosome, Gene, Locus, and Allele. This diagram shows how the concepts of chromosome, gene, locus, and allele are related. What is the difference between a gene and a locus? Between a gene and an allele?
    ::染色体、 Gene、 Locus 和 Allele 。 这个图表显示了染色体、 基因、 病原体和 Allele 的关联性。 基因和病原体的区别是什么? 基因和病原体的区别是什么? 基因和病原体的区别是什么? 基因和病原体的区别是什么?

     

    Genotype
    ::热基因类型

    When occurs, sex (called gametes) unite during to form a single cell called a zygote . The zygote inherits two of each type of chromosome, with one chromosome of each type coming from the father, and the other coming from the mother. Because homologous chromosomes have the same genes at the same loci, each individual also inherits two copies of each gene. The two copies may be the same allele or different alleles. The alleles an individual inherits for a given gene make up the individual’s genotype .  As shown in the table , an organism with two of the same allele (for example,  BB or bb ) is called a  homozygote . An organism with two different alleles (in this example,  Bb ) is called a heterozygote .
    ::当发生时,性(所谓的调子)在形成一个叫做zygote的单细胞时会团结起来。 zygote继承了两种染色体,一种是父亲的染色体,另一种是母亲的染色体。 因为同质染色体在同一地方有相同的基因, 每个人也继承了两种基因的复制件。 两种复制件可以是同异性, 也可以是不同的异性。 一个人继承给定基因的异性构成个人的基因类型。 如表所示, 具有两种同异性( 例如BB或bbb) 的有机体称为同质基因。 两种异性( 例如Bb) 的有机体被称为异性。

     
    Alleles Genotypes Phenotypes
      BB (homozygote) purple flowers
    B (purple) Bb (heterozygote) purple flowers
    b (white) bb (homozygote) white flowers

    Phenotype
    ::色型

    The expression of an organism’s genotype is referred to as its phenotype , and it refers to the organism’s traits, such as purple or white flowers in pea plants. As you can see from the table above, different genotypes may produce the same phenotype. In this example, both BB and Bb genotypes produce plants with the same phenotype, purple flowers. Why does this happen? In a Bb heterozygote, only the B allele is expressed, so the b allele doesn’t influence the phenotype. In general, when only one of two alleles is expressed in the phenotype, the expressed allele is called dominant, and the al lele that isn’t expressed is called recessive .
    ::有机体基因型的表达方式被称为其苯型,它指的是有机体的特性,比如豆类植物中的紫花或白花。 从上表可以看出,不同的基因型可能产生相同的苯型。在这个例子中,生物体和Bb基因型都产生同一种苯型植物,即紫色花。为什么会发生这种情况呢?在Bb heterozygote中,只有Belele表示,所以Bele并不影响苯型。 一般来说,当两种异类中只有一种以苯型表示时,表示的异型被称为主要,而没有表示的异型则被称为休眠。

    The terms dominant and recessive may also be used to refer to phenotypic traits. For example, purple flower color in pea plants is a dominant trait. It shows up in the phenotype whenever a plant inherits even one dominant allele for the trait. Similarly, white flower color is a recessive trait. Like other recessive traits, it shows up in the phenotype only when a plant inherits two recessive alleles for the trait.
    ::支配性词和隐性词也可以用来指胎儿的特征。例如,豆类植物中的紫花色是一种主要特征。当植物继承一个占支配地位的异性物时,它就会出现在阳性类型中。同样,白花色也是一种隐性特征。与其他隐性特征一样,它只有在植物继承两个属于该特性的静性异性物时,它才会出现在阴性类型中。

    Summary
    ::摘要

    • Mendel's laws of inheritance, now expressed in terms of genes, form the basis of genetics, which is the science of heredity . This is why Mendel is often called the father of genetics.
      ::孟德尔的继承法现在以基因的形式表达,它构成了遗传学的基础,而遗传学正是遗传学的科学。 这就是为什么门德尔常常被称为遗传学之父。
    • A gene is the part of a chromosome that codes for a given protein. The position of a gene on a chromosome is its locus.  A given gene may have different versions, called alleles.  Paired chromosomes of the same type are called homologous chromosomes. They have the same size and shape, and they have the same genes at the same loci.
      ::基因是染色体的一部分,该染色体是给定蛋白的代号。染色体上的基因位置是其位置。给定的基因可能有不同的版本,叫做异性。同类的同种染色体被称为同种染色体。它们大小和形状相同,同一种异种的基因相同。
    • The alleles an individual inherits for a given gene make up the individual's genotype. An organism with two of the same allele is called a homozygote, and an individual with two different alleles is called a heterozygote.
      ::个体继承给定基因的等同基因构成个人的基因型。 同一基因型中的两种有机体被称为同子体,而两个异异子体则被称为异体。
    • The expression of an organism's genotype is referred to as its phenotype. A dominant allele is always expressed in the phenotype, even when just one dominant allele has been inherited. A recessive allele is expressed in the phenotype only when two recessive alleles have been inherited.
      ::有机体基因型的表达方式被称为其pheno类型。 支配型异名总是以苯型表示, 即使只继承了一个占支配地位的异名。 只有当两个隐性异名被继承时, 才会以苯型表示中性异名。

    Review
    ::回顾

    1. Define genetics.
    ::1. 界定遗传学。

    2. Why is Gregor Mendel called the father of genetics if genes were not discovered until after his death?
    ::2. 如果基因直到Gregor Mendel死后才被发现,为何他被称为基因之父?

    3. Correctly use the terms gene, allele, locus , and chromosome in one or more sentences.
    ::3. 在一个或多个句子中正确使用基因、阿列尔、体积和染色体等术语。

    4. Compare and contrast genotype and phenotype.
    ::4. 比较和对比基因型和苯型。

    5. Imagine that there are two alleles, R and r , for a given gene. R is dominant to r . Answer the following questions about this gene.
    ::5. 想象一个特定基因有两种异变,R和r,R主要为r.,回答关于这个基因的下列问题。

    a. What are the possible homozygous and heterozygous genotypes?
    ::a. 可能的同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系同系

    b. Which genotype or genotypes express the dominant R phenotype? Explain your answer.
    ::b. 哪种基因型或基因型表示主要的R苯型?解释你的答复。

    c. Are R and r on different loci? Why or why not?
    ::c. R和r是否在不同地点?

    d. Can R and r be on the same exact chromosome? Why or why not? If not, where are they located?
    ::d. R和 r 是否在同一染色体上?为什么或为什么没有?如果没有,它们在哪里?

     

    6. If a child has the genotype Dd and inherited the D from their mother, where did the d likely come from?
    ::6. 如果儿童具有基因型Dd并从母亲那里继承D,那么可能来自何处?

    a. either their mother or their father
    ::a. 其母亲或父亲

    b. their father
    ::b. 他们的父亲

    c. their maternal grandmother
    ::c. 其祖母祖母

    d. their maternal grandfather
    ::d. 其外祖父

     

    7. True or False:  Each phenotype has only one genotype.
    ::7. 真实或假:每种苯型只有一个基因型。

     

    8. True or False:  Recessive genes are never expressed in a phenotype.
    ::8. 真实或假基因:坏基因从未以苯型表示。

     

    9. True or False:  An observable physical trait is a phenotype.
    ::9. 真实或假:可观察到的物理特征是一种苯型。

     

    10. A gene for flower color and a gene for seed shape could be on the same:
    ::10. 花色基因和种子形状基因可以相同:

    a. chromosome
    ::a. 染色体

    b. locus
    ::b. 地 地

    c. allele
    ::c. 全部

    d. both A and B
    ::d. A 和 B 两者

     

    11. A gene usually codes for a given _________ .
    ::11. 给定基因的基因密码通常为__________________________________________________________________________________________________________