These all relate to exceptions to the inheritance patterns encountered by Mendel. Why do multiple and lethal alleles often result in modifications of the classic Mendelian monohybrid and dihybrid ratios? Select the four correct statements.-When an essential gene is mutated, it can result in a lethal phenotype. There are no classic Mendelian monohybrid and dihybrid ratios.-In the case of codominance, heterozygotes produce gene products from both alleles of a gene. Classic Mendelian monohybrid and dihybrid ratios are modified by codominance.-In the case of incomplete dominance, the phenotype of the heterozygote is distinct from and often intermediate to the phenotypes of homozygous individuals. Classic Mendelian monohybrid and dihybrid ratios are modified by incomplete dominance.-Genes exist in a large number of allelic versions and a diploid organism has two homologous gene loci that may be occupied by different alleles of the same gene. This can result in many different phenotypes for traits, which may not follow typical Mendelian ratios.-When an essential gene is mutated, it can result in a lethal phenotype. This results in a modification of classic Mendelian ratios.-The phenotype of the heterozygous genotype is distinct from and often intermediate to the phenotypes of the homozygous genotypes. The joint expression of both alleles in a heterozygote is called codominance. There are no classic Mendelian monohybrid and dihybrid ratios.-Genes exist in a large number of allelic versions, but in a diploid organism, only one allele of the gene can occupy one homologous gene loci. Classic Mendelian inheritance cannot explain this phenomenon.-Each gene produces a unique gene product. The effect of one allele in a heterozygote completely masks the effect of the other. Classic Mendelian genetics cannot explain this phenomenon. Solution Answers: Correct statements: 2. In the case of codominance, heterozygotes produce gene products from both alleles of a gene. Classic Mendelian monohybrid and dihybrid ratios are modified by codominance. (Codominance) 3. In the case of incomplete dominance, the phenotype of the heterozygote is distinct from and often intermediate to the phenotypes of homozygous individuals. Classic Mendelian monohybrid and dihybrid ratios are modified by incomplete dominance. (Incomplete dominance) 4. Genes exist in a large number of allelic versions and a diploid organism has two homologous gene loci that may be occupied by different alleles of the same gene. This can result in many different phenotypes for traits, which may not follow typical Mendelian ratios. (Multiple alleles) 5. When an essential gene is mutated, it can result in a lethal phenotype. This results in a modification of classic Mendelian ratios. (Lethal gene).

1. These all relate to exceptions to the inheritance patterns encountered by Mendel.
Why do multiple and lethal alleles often result in modifications of the classic Mendelian
monohybrid and dihybrid ratios?
Select the four correct statements.-When an essential gene is mutated, it can result in a lethal
phenotype. There are no classic Mendelian monohybrid and dihybrid ratios.-In the case of
codominance, heterozygotes produce gene products from both alleles of a gene. Classic
Mendelian monohybrid and dihybrid ratios are modified by codominance.-In the case of
incomplete dominance, the phenotype of the heterozygote is distinct from and often intermediate
to the phenotypes of homozygous individuals. Classic Mendelian monohybrid and dihybrid
ratios are modified by incomplete dominance.-Genes exist in a large number of allelic versions
and a diploid organism has two homologous gene loci that may be occupied by different alleles
of the same gene. This can result in many different phenotypes for traits, which may not follow
typical Mendelian ratios.-When an essential gene is mutated, it can result in a lethal phenotype.
This results in a modification of classic Mendelian ratios.-The phenotype of the heterozygous
genotype is distinct from and often intermediate to the phenotypes of the homozygous
genotypes. The joint expression of both alleles in a heterozygote is called codominance. There
are no classic Mendelian monohybrid and dihybrid ratios.-Genes exist in a large number of
allelic versions, but in a diploid organism, only one allele of the gene can occupy one
homologous gene loci. Classic Mendelian inheritance cannot explain this phenomenon.-Each
gene produces a unique gene product. The effect of one allele in a heterozygote completely
masks the effect of the other. Classic Mendelian genetics cannot explain this phenomenon.
Solution
Answers:
Correct statements:
2. In the case of codominance, heterozygotes produce gene products from both alleles of a gene.
Classic Mendelian monohybrid and dihybrid ratios are modified by codominance.
(Codominance)
3. In the case of incomplete dominance, the phenotype of the heterozygote is distinct from and
often intermediate to the phenotypes of homozygous individuals. Classic Mendelian monohybrid
and dihybrid ratios are modified by incomplete dominance. (Incomplete dominance)
4. Genes exist in a large number of allelic versions and a diploid organism has two homologous
gene loci that may be occupied by different alleles of the same gene. This can result in many
different phenotypes for traits, which may not follow typical Mendelian ratios. (Multiple alleles)

2. 5. When an essential gene is mutated, it can result in a lethal phenotype. This results in a
modification of classic Mendelian ratios. (Lethal gene)