Inheritance key words
Introduced| English | Meaning |
|---|---|
| alleles/əˈliːlz/ | Alternative versions of a gene found at the same locus on a chromosome. |
| dominant/ˈdɒmɪnənt/ | Describing an allele whose effect is expressed in a heterozygote. |
| recessive/rɪˈsesɪv/ | Describing an allele whose effect is masked by a dominant allele in a heterozygote. |
| genotype/ˈdʒenətaɪp/ | The genetic constitution of an organism, or the alleles it has at specified loci. |
| phenotype/ˈfenətaɪp/ | The observable characteristics of an organism, resulting from its genotype and environmental influences. |
| homozygous/ˌhɒməˈzɪɡəs/ | Two same alleles. |
| heterozygous/ˌhetrəˈzɪɡəs/ | Having two different alleles at a particular gene locus. |
The language of inheritance
- To understand how characteristics pass from parents to children, you need the right words.
- A few key terms unlock all of genetics.
An allele is:
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Alleles are different versions of a gene.
A dominant allele:
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One dominant allele is enough to show the trait.
An allele that only shows its effect when two copies are present is ______.
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A recessive trait needs a homozygous recessive genotype.
Alleles 等位基因, dominant 显性 and recessive 隐性
- A gene can have different versions called alleles.
- A dominant allele shows its effect even if only one copy is present; a recessive allele shows only with two copies.
DNA carries inherited information in its double-helix structure
Predicting a genetic cross
A Punnett square shows the possible combinations of alleles offspring can inherit from two parents.
The genotype of an organism is:
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Genotype = the alleles; phenotype = the visible trait.
Match each genetics word to its meaning.
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Alleles are gene versions; genotype is what alleles you have, phenotype is what shows.
Genotype 基因型 and phenotype 表现型
- Genotype: the alleles an organism has (e.g. Bb).
- Phenotype: the characteristic you can see (e.g. brown eyes).
A heterozygous genotype has:
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Heterozygous = two different alleles.
Homozygous 纯合子 and heterozygous 杂合子
- Homozygous: two same alleles (BB or bb).
- Heterozygous: two different alleles (Bb).
A recessive trait needs two recessive alleles. A single recessive allele is hidden by a dominant one. The recessive characteristic only appears in a homozygous recessive genotype (e.g. bb).
You've got it
- a gene has versions called alleles; dominant shows with one copy, recessive needs two
- genotype = the alleles (Bb); phenotype = the visible characteristic
- homozygous = two same alleles; heterozygous = two different