Download Non Mendelian Genetics - Warren County Schools

Complex Pa+erns of Heredity Incomplete Dominance •  Some traits are neither totally dominant or recessive •  Heterozygous offspring inherit a trait that is a blend •  Example: red snapdragon x white snapdragon= pink snapdragon Incomplete dominance C-­‐ curly hair C -­‐ straight hair Genotypes for: Curly? Wavy? Straight? Incomplete Dominance PracIce •  Predict the genotypes and phenotypes of offspring created by crossing a blue fish and a yellow fish. Blue is incompletely dominant to yellow. Codominace: Both alleles in a heterozygous match express themselves fully (“C” represents the gene for coat color) CR = red allele for coat color; CW= white allele for coat color In ca+le, red hair is co-­‐dominant to white hair. Produces a roan cow that is speckled with white & red. Show the genotypes of the cows below. 5
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Chickens – black & white feather color is codominant resulIng in a speckled chicken What is the genotype of a “speckled chicken”? 6
–  Codominant alleles are neither dominant nor
recessive.
–  The ABO blood types result from codominant
alleles.
Type of protein in the picture above that
helps cells recognize each other is called?
MulIple Alleles and Codominance •  Many genes have more than two alleles ex. Blood Type IA or IB or i (I= inherit a glycoprotein) (i= don’t inherit a glycoprotein) Type A? Type B? Type AB? Type O? Codominance Problem Example: homozygous male Blood Type B ( ) x heterozygous female Blood Type A ( ) 9
Males and females can differ in sex-­‐linked traits. •  Genes on sex chromosomes are called sex-­‐
linked genes. –  Y chromosome genes in mammals are responsible for male characterisIcs. –  X chromosome genes in mammals affect many traits Example of Sex-­‐Linked Traits InheriIng Sex Linked Traits •  Sex Linked Traits are inherited on the X chromosome. •  How would a male inherit the gene for colorblindness? •  How could a female be colorblind? •  Who is more likely to display a colorblind trait? Other Examples: Hemophilia, Baldness, Calico Cats A pedigree is a chart for tracing genes in a family •  Phenotypes are used to infer genotypes on a pedigree. •  Autosomal genes show different pa+erns on a pedigree than sex-­‐linked genes. If the phenotype is more common in males, the
gene is likely sex-linked.