inheritence and genetics Flashcards
(22 cards)
what were mendel’s 3 laws
law of segregation
law of independent assortment
law of dominance
law of segregation
sex cells form in meiosis, will contain 1 form of each gene
law of independent assortment
separation of variant forms of genes (alleles) into sex cells isn’t affected by how other allele gets put in
law of dominance
if an organism has a dominant allele that trait will be expressed
why didn’t ppl trust mendel’s research (6)
-didn’t know about chromosomes
-preconceived theories
-his approach was a novel concept
-not part of academic establishment
-results not corroborated
-peas had unusual results
monogenic meaning
controlled by one gene e.g. dimples
polygenic meaning
controlled by many genes e.g. height
what is polydactyly
-condition meaning ppl have extra digits
-dominant
what is cystic fibrosis
-disorder of cell membranes (creates mucus)
-recessive
what is sickle cell disease
-blood cells are sickle shaped
-recessive
symptoms of CF (4)
-dilated airways
-blood in mucus
-thick, sticky mucus blocks airways
-bacterial infection
symptoms of sickle cell disease (6)
-painful blood clots
-fatigue
-anaemia
-brain damage
-physical weakness
-danger to/failure of heart + kidneys
what is a pedigree chart
genetic diagram showing genetic relationship between individuals as well as their phenotypes
what is codominance
both alleles are expressed in same phenotype
example of codominance
blood type A and B
which blood group is recessive
O
how do sex-linked genetic disorders work
-allele is located on X or Y
-Y chromosome is smaller so carries fewer genes, so most genes on gametes are only on X
-males only have 1 X so often only have 1 allele for sex-linked genes
-bc of this trait will show even if recessive
what can cause mutation
-random mistakes in replication
-radiation
-chemical carcinogens
what are the 4 differences that can happens in DNA sequences
-substitution
-insertion
-deletion
-inversion
what is an allele
different version of the same gene
what is a mutation
change in base sequence of DNA meaning a non-functioning protein may be created
what is variation
differences that exist between individuals within species
