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6.4 Traits, Genes, and Alleles KEY CONCEPT Genes encode proteins that produce a diverse range of traits.
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6.4 Traits, Genes, and Alleles The same gene can have many versions. A gene is a piece of DNA that directs a cell to make a certain protein. Each gene has a locus, a specific position on a pair of homologous chromosomes. The locus is like the gene’s Address on the chromosome
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6.4 Traits, Genes, and Alleles An allele is any alternative form of a gene occurring at a specific locus on a chromosome. –Each parent donates one allele for every gene. –Homozygous describes two alleles that are the same at a specific locus. –Heterozygous describes two alleles that are different at a specific locus.
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6.4 Traits, Genes, and Alleles Genes influence the development of traits. All of an organism’s genetic material is called the genome. A genotype refers to the makeup of a specific set of genes. -the genotype tells you the two alleles an organism has for a specific trait A phenotype is the physical expression of a trait. Phenotype tells you what trait is expressed( how they look)
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6.4 Traits, Genes, and Alleles Alleles can be represented using letters. –A dominant allele is expressed as a phenotype when at least one allele is present in the pair. –A recessive allele is expressed as a phenotype only when two copies are present. –Dominant alleles are represented by uppercase letters; recessive alleles by lowercase letters.
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6.4 Traits, Genes, and Alleles Both homozygous dominant and heterozygous genotypes yield a dominant phenotype. Most traits occur in a range and do not follow simple dominant-recessive patterns.
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6.4 Traits, Genes, and Alleles Pea shape Phenotypegenotype Pea color Flower color Pod shape Pod color Flower position Plant height
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6.4 Traits, Genes, and Alleles Pea shape Phenotypegenotype round Wrinkled
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6.4 Traits, Genes, and Alleles Pea shape Phenotypegenotype roundRR, Rr Wrinkledrr
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6.4 Traits, Genes, and Alleles Pea color Phenotypegenotype yellowYY, Yy greenyy
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6.4 Traits, Genes, and Alleles Mendel observed patterns in the first and second generations of his crosses.
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6.4 Traits, Genes, and Alleles Pea color Phenotypegenotype yellowYY, Yy greenyy
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6.4 Traits, Genes, and Alleles Mendel observed patterns in the first and second generations of his crosses.
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6.4 Traits, Genes, and Alleles Pea shape Pea color
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6.4 Traits, Genes, and Alleles Mendel observed patterns in the first and second generations of his crosses.
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6.4 Traits, Genes, and Alleles flower color Phenotypegenotype purplePP, Pp whitepp
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6.4 Traits, Genes, and Alleles Mendel observed patterns in the first and second generations of his crosses.
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6.4 Traits, Genes, and Alleles Pod shape Phenotypegenotype smoothSS, Ss constrictedss
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6.4 Traits, Genes, and Alleles Mendel observed patterns in the first and second generations of his crosses.
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6.4 Traits, Genes, and Alleles Pod color Phenotypegenotype GreenGG, Gg yellowgg
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6.4 Traits, Genes, and Alleles Mendel observed patterns in the first and second generations of his crosses.
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6.4 Traits, Genes, and Alleles Flower position Phenotypegenotype axialAA, Aa terminalaa
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6.4 Traits, Genes, and Alleles Plant height Phenotypegenotype tallTT, Tt shorttt
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