Chapter 4 Flashcards
Genes
units of heredity that maintain their structural identity from one generation to another.
Chromosomes
strands of genes that also come in pairs.
RNA
controls sequence of amino acids in a protein molecule.
dominant gene
shows a strong effect in either the homozygous or heterozygous condition.
homozygous
If you have the same genes on your two copies of some chromosome,
heterozygous
If you have an unmatched pair of genes
Four bases of DNA
adenine, guanine, cytosine, and thymine.
recessive gene
shows its effects only in the homozygous condition.
sex-linked genes
genes on the sex chromosomes (X and Y).
Red-green color deficiency
- a sex linked gene
- most common in men
sex-limited genes
present in both sexes but active mainly in one sex.
mutation
a heritable and permanent change in a DNA molecule.
epigenetics
deals with changes in gene expression.
Methylation
Adding a methyl group turns genes off.
Acetyl groups
An acetyl group loosens histone’s grip and increases gene activation.
monozygotic twins
- identical.
- have same genes.
dizygotic twins
- fraternal
candidate gene approach
examination of a single gene and it’s association with a behaviour based on theory.
genome wide association study
examine all genes and determine differences
between two groups with a particular behavior of interest.
phenylketonuria (PKU)
a genetic inability to metabolize the amino acid phenylalanine.
- can lead to mental retardation if not treated.
evolution
a change over generations in the frequencies of various genes in a population.
artificial selection
choose individuals with a desired trait and make them the parents of the next generation.
lamarckian evolution
principle that physical changes in organisms during their lifetime could be transmitted to their offspring.
fitness
the number of copies of ones genes that endure in later generations.
- improved by evolution.