Mendelian Inheritance Most human traits are polygenic; meaning they are controlled by more than one...
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Transcript of Mendelian Inheritance Most human traits are polygenic; meaning they are controlled by more than one...
![Page 1: Mendelian Inheritance Most human traits are polygenic; meaning they are controlled by more than one gene Pedigrees are tools used by geneticists to.](https://reader036.fdocuments.us/reader036/viewer/2022082713/5697c0031a28abf838cc380b/html5/thumbnails/1.jpg)
Mendelian Inheritance
Most human traits are polygenic; meaning they are controlled by more than one gene
Pedigrees are tools used by geneticists to trace a trait back through a family line or help predict traits of offspring
![Page 2: Mendelian Inheritance Most human traits are polygenic; meaning they are controlled by more than one gene Pedigrees are tools used by geneticists to.](https://reader036.fdocuments.us/reader036/viewer/2022082713/5697c0031a28abf838cc380b/html5/thumbnails/2.jpg)
Simple Recessive Heredity
An individual must have two copies of an allele to express a certain trait
Ex Cystic fibrosis Tay-Sachs Disease Phenylketonuria (PKU)
![Page 3: Mendelian Inheritance Most human traits are polygenic; meaning they are controlled by more than one gene Pedigrees are tools used by geneticists to.](https://reader036.fdocuments.us/reader036/viewer/2022082713/5697c0031a28abf838cc380b/html5/thumbnails/3.jpg)
Simple Dominant Heredity
Follows Mendelian rules of dominance; an individual only needs one allele for the trait to be visible in the phenotype
EX: Tongue curling Hitchhiker’s thumb Huntington’s disease
![Page 4: Mendelian Inheritance Most human traits are polygenic; meaning they are controlled by more than one gene Pedigrees are tools used by geneticists to.](https://reader036.fdocuments.us/reader036/viewer/2022082713/5697c0031a28abf838cc380b/html5/thumbnails/4.jpg)
Complex Patterns of Inheritance
Incomplete dominance – a heterozygous individual has a blend or mix of the parental phenotypes; pink flowers
Codominance – both alleles are expressed in the phenotype of a heterozygous individual; checkered chickens
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Multiple phenotypes from multiple alleles – a trait is controlled by more than 2 versions of the gene; ABO blood typing
Sex determination – determined by acquiring an X or a Y chromosome from the male parent, the female parent donates only an X
![Page 6: Mendelian Inheritance Most human traits are polygenic; meaning they are controlled by more than one gene Pedigrees are tools used by geneticists to.](https://reader036.fdocuments.us/reader036/viewer/2022082713/5697c0031a28abf838cc380b/html5/thumbnails/6.jpg)
Sex-linked inheritance – a trait located on the sex chromosomes usually referring to traits on the X chromosome
Polygenic (traits) inheritance – multiple genes code for 1 trait, like eye color
![Page 7: Mendelian Inheritance Most human traits are polygenic; meaning they are controlled by more than one gene Pedigrees are tools used by geneticists to.](https://reader036.fdocuments.us/reader036/viewer/2022082713/5697c0031a28abf838cc380b/html5/thumbnails/7.jpg)
Environmental Influences
Factors, other than genetics, that affect an organism’s phenotype
External factors: nutrition, light, chemicals, temperature, infection
Internal factors: hormones, structural differences
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Changes in Chromosome number
When humans have a number of chromosomes other than 46
EX: Down syndrome – trisomy 21 Turner’s syndrome – XO – only one X
chromosome Klinefelter’s syndrome – XXY