DNA Flashcards
What is the formula for crossover frequency
of recombiants/total # of offspring x 100
Why are genes said to be linked?
Because theres so many on one chromsome that during crossover its very likely that they stick together, the closer they are
What is a recombiant
The term given to an offspring which would not have been possible if crossing over had not occured
Evdience of Autosomal reccessive in pedigrees
- Traits skip a gen
- unaffects parents that are carriers
- parents of offspring who have the trait are hetero
- homozygous individuals only have the trait
Evidence of autosomal dominant in peidgrees
Traits dont skip a generation
an effcted offspring cant have two unaffected parents- at least one will have it
Evidence of x-linked reccessive in pedigrees
More males than females are affected
all daughters of a male are heterozygous
Evidence of x-linked dominant in pedigress
All affects males have all affected daugghters
no male to male trasnmission
What are polygenic traits
Traits that are controlled by more than one gene
what are epistatic genes
genes that interfere with the expression of another gene EX: theres a gene for white and black pigment but theres also a gene for if theres any pigment at all
What is a true parent
When the parents can only produce one gamete EX: YYRR it will always produce a YR gamete
What does it mean by genes assort independently
One gene does not infleunce the inheritance of another
What is co-dominance
They can both be dominantly seen but its spotty
What is incomplete dominiance
When they are blended together
Who is Thomas Morgan Hunt
- fruit fly guy
- identified that some genes are inherited on the x chromosomes
What does it mean to be hemizygous
males are hemizygous for some stuff becaus ethey have only one x chromosome
What is the law of unit Characteristics
Traits are controlled by genes which come in pairs , one from each parent
WHat is the law of dominance
The dominant form of a trait will prevent the expression of a recessive form
What is the law of segragation
Gametes will have one copy of each homologus chromosome - during emisosis the copies will seperate
What is the Law of Independent assortment
Chromosomes are assort indpendantly during meisosis, one chromosme doesnt affect where another chromsome will go
What did mendel study
Peas
What is Heredity
The passing of traits from parents to offspring
