genetics Flashcards
how many alleles does an individual carry for a trait?
2
explain the following principles(laws) associated with mendel
principle of dominance: some alleles are dominant and others are recessive and dominant is always shown if present
principle of segregation: separation of alleles during gamete formation
principle of independent assortment: genes for different traits can segregate independently during the formation of gametes
what is the relationship between the following terms: gene, trait, DNA
there are many genes that make up our dna that help control our traits
in humans, free earlobes (F) are dominant to attached earlobes (f)
write the genotypes of the following
a) a person who is homozygous for free earlobes: FF
b) a person who is heterozygous for free earlobes: Ff
c) a person who is homozygous for attached earlobes: ff
what is incomplete dominance?
cases in which one allele is not completely dominany over another
white + red -> pink [BLENDING]
what is codominance?
cases in which the phenotypes produced by both alleles are clearly expressed
[black and spotted chicken]
what is a polygenic inheritance and what does its graph look like?
trait controlled by many genes
bell curve on a graph
what are the possible gametes for a person who has BbTt genotype?
BT bT Bt bt
which parent determines the sex of the child? why?
the male, they can give “x” or “y” females can only give “x’s”
free earlobes is an autosomal dominant trait and attached earlobes are recessive. what is the genotype of a carrier?
Tt
why do females show recessive sex-linked traits less often thans males?
because they have to have the recessive allele on both chromosomes
distinguish between autosomes and sex-chromosomes
sex chromosomes determine ones sex and theres two of them
autosomes are all the other 44 chromosomes
what is the sex chromosome combo of a normal male? & a normal female? and which comes from each parent?
Male: XY
Female: XX
males can pass one x or one y
females pass down one x all the time
what is a pedigree?
a chart that helps shows the absence or presence of a trait according to the relationship between parents, siblings, and offspring
