genetics and heredity Flashcards
what is heredity?
the passing of traits from parents to offspring
what is a trait?
an observed characteristic
in a punnet square, where is the male?
on top, female along the side
what does the punnet square show?
it is the summary of every possible combination of one maternal allele with one paternal allele for each gene being studied in the cross
how many traits does the monohybrid cross look at?
one
what is a pedigree chart used for?
to track inherited diseases in families
what only works with traits that are monogenic?
dihybrid crosses
what did mendel’s model of inheritance assume?
- each trait is controlled by a single gene, 2.there is a clear dominant recessive relationship between the alleles, 3.each gene has only 2 alleles. most traits and genes do NOT satisfy this criteria
what does pleiotropy mean?
it refers to an allele which has more than one effect on the phenotype, can be seen in cystic fibrosis and ickle cell anemia. multiple symptom can be traced back to one defective allele
in loci 22q12.2, what doe the 22 and 12.2 mean?
22 is the chromosome number, 12.2 indicates the position on the arm