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Variations to Inheritance. Exceptions to Mendel’s Laws. Other Inheritance Patterns. There are other ways that traits are inherited Scientist found out there are excepts to Mendel’s experiments Incomplete Dominance Codominance X-Linked Traits (Sex-Linked) Multiple Alleles Polygenic Traits.
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Variations to Inheritance Exceptions to Mendel’s Laws
Other Inheritance Patterns • There are other ways that traits are inherited • Scientist found out there are excepts to Mendel’s experiments • IncompleteDominance • Codominance • X-Linked Traits (Sex-Linked) • Multiple Alleles • Polygenic Traits
Incomplete Dominance • When an allele is not completely dominant over the other. • Results in the offspring having a “blending” phenotype • Example : Red Flowers X White Flowers _pink flowers
Codominance • When both alleles Are expressed. Both are Dominant. Example – A cow with brown and white coat Think?????? - A pink plant and a white plant were crossed and the offspring exhibited codominance. What would the offspring look like?
X-Linked Traits • Traits found on the sex chromosomes • Some inheritance is autosomal – on the other 22 pairs chromosomes, while others are only found on the 23 pair chromosome, known as one the sex chromosome. • Typically affect more males than females!
X-Linked Examples • Color Blindness – unable to see certain colors such as red and green • Hemophilia – disease where the blood is unable to clot.
Multiple Alleles • More than two forms of alleles • Our blood type is an example of a trait with more than 2 alleles • Blood Types • A • B • O
Blood Groups • An A blood type can have either AA allele or AO allele • B Blood types will have BB or BO • AB blood type will be AB • An O blood type will be OO
Polygenic Traits • When multiple alleles control one trait it is considered polygenic. • Example such as skin color, height, eye color, or fingerprints are polygenic traits.