Genetic Inheritance, Chromosome Variation, and Gene–Environment Effects

All flashcards

Allele

One of the alternative forms of a gene.

Phenotype

An organism’s observable characteristics, shaped by genetic instructions and potentially by environmental influences.

X-linked gene

A gene located on the X chromosome.

DNA methylation

An epigenetic mechanism in which chemical methyl groups are added to or removed from DNA, affecting gene expression.

Gene–environment correlation (rGE)

A pattern in which genetic tendencies are associated with the environments a person experiences.

Quiz questions

1. A person inherits an A allele and a B allele for the ABO blood group. Which inheritance pattern explains expression of both alleles in type AB blood?Answer: Codominance.
2. What does a heritability estimate describe?Answer: The proportion of trait variation in a particular population and context associated with genetic differences.
3. What can adding methyl groups to DNA do to gene expression?Answer: It can silence or reduce expression of a gene.
4. Biological parents provide a child with both inherited genetic tendencies and a home environment correlated with those tendencies. Which type of gene–environment correlation is this?Answer: Passive rGE.
5. Down syndrome is commonly associated with which chromosome abnormality?Answer: Trisomy 21.