Chapter 10 Flashcards
Dominant
The trait expressed
Recessive
The trait not expressed
Genes
Information about traits that is transmitted from parent to offspring.
Heterozygous
One dominant and one recessive allele, Ee
Homozygous dominant
Two dominant alleles, EE
Homozygous recessive
Two recessive alleles, ee
Alleles
Alternate forms of a gene.
Example: unattached earlobe and attached earlobe
Phenotype
Refers to an individuals appearance
Genotype
Refers to an individuals alleles
Incomplete dominance
Not all alternative alleles are fully dominant or fully recessive in heterozygotes. Produce a heterozygous phenotype that is intermediate between those of the parents.
Ratios
1:2:1
True breeding dominant: not-true-breeding dominant: true breeding recessive
What technique can be used to determine the genetic inheritance of offspring when the parents have known genotypes?
Punnett square
Law of segregation
The two alleles of a trait separate during the formation of gametes, so that half of the gametes will carry one copy and half will carry the other copy.
Law of independent assortment
- The inheritance of one trait does not influence the inheritance of the other trait.
- Genes located on different chromosomes are inherited independently of one another.
Dihybrid cross
Examining the inheritance of two separate traits
Monohybrid cross
Examines the inheritance of one trait
Sex-linked traits
A trait determined by a gene in the sex chromosome
Sex chromosomes
In humans, the X and Y chromosomes, which are different in the two sexes and are involved in sex determination
Autosomes
Any of the 22 pairs of human chromosomes that are similar in size and morphology in both males and females
Testcross
- A cross between and individual of unknown genotype and recessive homozygous.
- Used to determine a dominant individual’s genotype.
