BIOL239 Lecture Notes - Lecture 2: Sickle-Cell Disease, Dihybrid Cross, Mendelian Inheritance
31 views2 pages
17 Apr 2016
School
Department
Course
Professor
Document Summary
Incomplete dominance: the f1 generation resembles neither purebred parent, rather, they show a mix of both (intermediate phenotype). Codominance: neither of the traits is dominant towards the other, but you see both traits in the offspring that are heterozygotes. Monomorphic: genes with only one wild-type allele. Polymorphic: genes with more than one wild type allele. Pleiotropic: multiple phenotypic effects caused by a single gene (i. e. sickle cell anemia). One gene, two alleles, changing many different phenotypes. Multifactorial inheritance: a phenotype arising from the action of two or more genes (polygenic) or from interactions between genes and the environment. Complementary gene action: two or more genes can work together in the same biochemical pathway to produce a particular trait. Heterogeneous trait: a mutation at any one of a number of genes can give rise to the same phenotype. Epistasis: a gene interaction in which the effects of an allele at one gene hides the effect of alleles at another gene.
Get access
Grade+
$40 USD/m
Billed monthly
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
10 Verified Answers
Class+
$30 USD/m
Billed monthly
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
7 Verified Answers
Related Documents
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. |