How do Mendelian genetics and non-Mendelian genetics differ in terms of inheritance patterns?

Answer 1

Mendelian Genetics - A display of complete dominance. The dominant allele is ALWAYS going to be 100% expressed in Homozygous Dominant and Heterozygous offspring.

A = Green, a = yellow

AA and Aa = Green

aa = yellow

Non-Mendelian Genetics

Codominance - There are two dominant alleles, and they both produce a phenotypic output. In blood types, this is due to both the proteins from IA and IB control different reactions independent of each other, allowing both to exist.

IA - Type A Blood

IB - Type B Blood

i - Type O Blood

IAIA and IAi = Type A

IBIB and IBi = Type B

IAIB = Type AB

ii = Type O

Incomplete Dominance - Where a dominant gene isn't fully expressed, leading to a "blending" of the parental phenotypes. It can be seen in heterozygous individuals.

A = Red

a = White

AA = Red

Aa = Pink (a blend of the two, due to the red protein not fully being expressed)

aa = White

Sex-Linked Inheritance - An allele being linked to one of the sex chromosomes. In XX individuals, only one of the X chromosomes is expressed so they have a higher chance of not expressing the X linked allele. XY individuals have a higher chance, since they only have one X chromosome. An example is color-blindness.

Some important concepts in Non-Mendelian Inheritance are Expressivity and Penetrance

Expressivity is the severity of the phenotypic output. Think of polydactly. Some people with this condition have a complete expression, which leads to atypical fingers on their hands. Some have a barely noticeable extra finger. Theres a spectrum between the two.

Penetrance is the percentage of individuals with the phenotypic output. Think of breast cancer. Out of all of the people with BRCA1 gene, only 22% will express the phenotype for cancer.

Answer 2

Mendelian genetics deals with two alleles,Dominant or recessive, and often involve the ratio 3:1 like with the pea plant study of Gregor Mendel. These pea plants color either had the dominant Purple (P) trait or they had non-dominant white trait (p) in the study.

Non-Mendelian inheritance were more complex, and harder to predict. It includes:

Incomplete dominance (example the pink flower combined with the white flower and it gives pink), codominance like a person with AB blood type,

polygenic inheritance: controlled by multiple genes that leads to variation

sex-linked inheritance: traits or disorders passed from parents from the sex chromosomes (X or Y)

Answer 3

Mendelian genetics follows simple dominant and recessive inheritance patterns, as described by Gregor Mendel. Non-Mendelian genetics includes more complex inheritance patterns like incomplete dominance, codominance, polygenic inheritance, and gene interactions.