BIOL 1201 Lecture Notes - Lecture 20: Intellectual Disability, Probability Distribution, Siamese Cat
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Result in changes in ratios of offspring, but alleles are inherited in the same manner. Incomplete dominance a situation in which the heterozygote has a different phenotype from the homozygotes. The heterozygous individuals have a phenotype intermediate to the homozygous individual: red x white pink. Any given gene may exist in more than two forms or alleles. Individual (diploid: no more than 2 alleles per gene. Population: no more than 2n alleles per gene. The result of genes located on one of the sex chromosomes (x or y), but not the other. One gene interferes with the expression of another. Phenylketonuria: mental retardation, reduced hair, and skin pigmentation. Multiple genes (polygenic traits) a situation in which multiple genes are involved in a particular trait results in continuous variation rather than discontinuous. many traits are the result of polygenic inheritance. Height, eye color, hair color, skin color additive effect of multiple genes.
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Related Questions
These all relate to exceptions to the inheritance patterns encountered by Mendel.â
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. |