genes & chromosomes. chromosome theory of heredity the factors (genes) that affect the...
DESCRIPTION
Crossing-Over Crossing-Over: The exchange of a section of DNA between chromosomes. Recombinants: Individual organism with a new combination of genes due to crossing-over.TRANSCRIPT
Genes & Chromosomes
Chromosome Theory of Heredity The factors (genes) that affect the
expression of traits are found on chromosomes.
The chromosome theory of heredity states: That genes are located on the chromosome and each gene occupies a specific place on that chromosome. Each chromosome contains just one allele for each of its genes.
Crossing-Over
Crossing-Over: The exchange of a section of DNA between chromosomes.
Recombinants: Individual organism with a new combination of genes due to crossing-over.
Mutations Mutation: Change in genetic material. Chromosomal Mutation: Change in number
or structure of chromosomes. Nondisjunction: Failure of chromosomes to
separate. Polypoidy: Extra set of chromosomes.
Gene Mutation: Change in the nucleotides of DNA. Point mutations: Single nucleotide. Frameshift mutation: The addition or deletion of a
base, altering DNA from the point of mutation on.
Sex Linkage Discovered by Nettie Stevens. Sex Chromosome: Chromosome that is
different in males (XY) and females (XX), determine the sex of an organism.
Autosomes: Chromosomes that are the same in males and females.
Sex-Linked: Trait that is determined by a gene located on a sex chromosome.
Regulation of Gene Expression Incomplete Dominance: Inheritance in which
an active allele does not entirely compensate for an inactive allele, results in a mixed phenotype (blended trait). Ex. Red Flower + White Flower = Pink
Flower Co-dominance: Condition in which both alleles
of a gene are expressed. Ex. A person with one blue eye and one green eye.
Polygenic Inheritance: A trait that is controlled by a multiple alleles of a genes (3 or more).