Unit 4 (chapters 9 & 10) Flashcards
(13 cards)
why do we have pairs of chromosomes?
-2 copies of every gene as a backup
-we all carry a certain amount o lethal genes, the 1 good copy of that gene keeps us alive
what is heredity?
-the passing of characteristics from parent to offspring through the parent’s genes
what are single-gene traits?
-some traits are determined by the instructions an organism carries on one gene
human characteristics are influenced by what?
-multiple genes
-the enviornment
what did Gregor Mendel do?
-father of genetics
-worked with peas since they had genetic diversity in a controllable way
what does Mendel’s theory of segregation state?
-there are 2 copies of each gene, but only one copy in each gamete
-a dominant trait masks the effect of recessive traits
important ideas from Mendel’s research?
-each parent puts a single set of genes into each sperm or egg it makes
-offspring receive 2 copies of the instructions of any trait
-the observed trait in an individual depends on the copies of a gene it inherits from its parents
generational labels
-1st gen = P0 (parental)
-2nd gen = F1 (filial)
-3rd gen = F2 (offspring of offspring)
difference between gene & allele?
-gene is the coding
-allele is what is actually expressed
difference between genotype and phenotype?
-genotype = either heterozygous or homozygous recessive/dominant genetic composition
-phenotype = the outward physical appearance
what is a test cross?
-reveals unknown genotypes
what is a pedigree ?
-used to document a trait of interest in humans across multiple generations family tree
-square = male
-circle = female
-gene of interest = shape will be colored in
**this can tell us if the gene is sex linked (X chromosome) or autosomal
what is incomplete dominance?
-the phenotype of a heterozygote is intermediate between the phenotypes of the two homozygotes
