Chapter 8 Heredity
Terms
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- Heredity
- The passing of characters from parents to offspring
- Genetics
- the branch of biology that focuses on heredity
- monohybrid cross
-
a cross that involves one pair of contrasting traits
Ex: crossing a plant with a purple flowers with a white flowers - true breeding
- all the offspring would display only one form of the character. EX: True breeding purple flowering plant will only produce plants with purple flowers in subsequent generations.
- P generation
-
The Parental generation
The first two individuals that are crossed in a breeding experiment -
F
1 Generation - The offspring from the P generation. (First Filial generation)
-
F
2 -
The offspring of the F
1
generation plants (second filial generation) - alleles
- Different versions of a gene
- dominant
- The expressed form of the character(character that is seen)
- recessive
- The trait that was not expressed. (It is there but not seen)
- homozygous
- If the two alleles of a particular gene present in an individual are the same
- heterozygous
- if the two alleles of a particular gene present in an individual are different
- genotype
- the set of alleles that an individual has for a character
- phenotype
- the physical apperance of a character
- Law of segregation
- the two alleles for a character segregate when gametes are formed
- law of independent assortment
- the alleles of different genes separate independently of one another during gamete formation
- Punnett square
- A diagram that predicts the outcome of a genetic cross by considering all possible combinations of gametes in the cross
- Test Cross
- The crossing of an individual of unknow genotype with a hymozygous recessive individuale to determine the unknown genotype
- Probability
- the likelihood that a specific event will occur.
- Pedigree
- a family history that shows how a trait is inherited over serveral generations
- sex-linked gene
- located on the x or y chromosome Moste are carried on the X and are recessive
- incomplete dominance
-
a phenotype that is intermediate between the two parents
Ex Red crossed with white=pink - polygenic inheritance
- when several genes influence a character. Example= eye color,height,weight,hair skin color
- multiple alleles
-
A gene with three or more alleles
EX Blood Type - codominance
-
Two dominant alleles are displayed at the same time.
EX Blood Types