Chapter 22 - Inheritance Flashcards
What is pure breeding?
When something is bred and it produces the same characteristic when bred among themselves
What are hybrids?
When an offspring has the genetic information for two traits but only expresses one
What is a mono hybrid cross?
The mating in which one pair of contrasting genes is studied
What is a gene?
The factor that determines an inherited characteristic that is found on a chromosome
What is an allele?
An alternative form of a gene
What is a dominant allele?
An allele that masks the effect of another allele, expresses itself in the heterozygous phenotype
What is a recessive allele?
An allele that is masked by the dominant gene and is only expressed when both genes are expressed in the homozygous condition
What is homozygous?
The situation where and individual has the same alleles for a particular characteristic
What is heterozygous?
The situation where an individual possesses different alleles for a particular characteristic
What is a phenotype?
The physical appearance of an individual as determined by the expression of the alleles for that characteristic
What is a genotype?
The genetic make-up of an individual as determined by the alleles for they characteristic being considered
What is the first filial generation?
The first generation of offspring produced after the cross of two parents
How is sex determined?
- all female eggs contain X chromosomes
- half of male sperm contain an X chromosome and the other half contain a Y chromosome
- it is the chromosomal complement of the fathers sperm that determines the sex of a child
What are autosomes?
The first 22 pairs of chromosomes that are not involved in sex determination
What is incomplete dominance?
- the dominant trait is not fully expressed
- the heterozygote is different from its pure bred parents
What is an example of incomplete dominance?
- snapdragon flowers
- red, white, pink
What is the principle of segregation?
The principle that during the production of gamete each gamete only receives one gene for each trait
What is codominance?
When a pair of different alleles both contribute to the phenotype and are equally expressed (but not blended) in a heterozygote
How are codominant allele written?
Both as capital letters as super scripts with one base letter
What is an example of codominance?
- shorthorn cattle
- red= R, white= W, roan= RW
What alleles make up the ABO blood group system?
A, B, O
