Non-Mendellian Traits What happens when its not all dominant ?
Non-Mendellian genetics
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Transcript of Non-Mendellian genetics
NON-MENDELLIAN PATTERNS OF INHERITANCE
HETEROZYGOATS
According to Mendel’s law, phenotypical characteristics are
determined by pairs of factors (alleles) that
separate independently in gametes.
Lack of Dominance
A genetic condition in which the heterozygous individual has a different phenotype from the homozygous individual.
Multiple Alleles
The phenomenon in which the same gene has more than two different alleles
Pleiotropy
Pleiotropy (or pliotropy) is the phenomenon in which a single gene conditions several different phenotypical traits.
Pleiotropy
Pleiotropy
Lethal Genes
Lethal genes are genes with at least one allele that, when present in the genotype of an individual, cause death.
Sex-linked Inheritance
A type of non-Mendelian inheritance because it opposes Mendel’s first law, which postulates that each trait is always conditioned by two factors (alleles).
Sex-linked Inheritance
Sex-linked traits are genetic characteristics determined by genes, which are located on sex chromosomes.
Sex-linked Inheritance
Sex-linked Inheritance
Gene Interactions
Gene interactions are the phenomenon in which a given phenotypic trait is conditioned by two or more genes
Gene Interactions
The three main types of gene interaction are: complementary genes, epistasis and polygenic inheritance (or quantitative inheritance).
Complementary Genes
Complementary genes are different genes that act together to determine a given phenotypic trait.
Epistasis
Gene interaction in which a gene (the epistatic gene) can disallow the phenotypical manifestation of another gene (the hypostatic gene).
Epistasis
In dominant epistasis, the inhibitor allele is the dominant allele (for example, I) of the epistatic gene and, as result, inhibition occurs in dominant homozygosity (II) or in heterozygosity (Ii).
Epistasis
In recessive epistasis, the inhibitor allele is the recessive allele of the epistatic gene (i) and, as a result, inhibition occurs only in recessive homozygosity (ii).
Polygenic Inheritance
Gene interaction in which a given trait is conditioned by several different genes with alleles that may or may not contribute to increasing the intensity of the phenotype.
Gaussian Curve
Pedigree Analysis
Hemophilia is a recessive, sex-linked disorder which causes an inability to clot when bleeding. Ray and Elaine Smith were married in 1970. Neither Ray nor Elaine had hemophilia. They had two daughters and then a son. Both daughters, Alicia and Candace, had normal clotting abilities and never had any children of their own.
Pedigree Analysis
The son, Mike, had hemophilia and married Beth, who did not. They had two children of their own, first Gregory and then Victoria. Surprisingly, Victoria had hemophilia but Gregory did not. Draw the pedigree that traces hemophilia in the Smith family, shade in the circles/squares of the individuals with the blood disorder.
Pedigree Analysis
a.) Why is it surprising that Victoria had hemophilia but Gregory did not?
b.) If Victoria has children, what do you automatically know about her… Daughters? Sons?
Very Short Quiz!
Briefly explain the following terms:
1. Incomplete Dominance2. Codominance3. Lethal Genes4. Gene Interaction5. Pedigree Analysis