Inheritance Flashcards
(54 cards)
in summary what did Mendel observe
true-breeding pea plants
produced genetically identical offspring
tall produced tall and short produced short
true breeding plants self pollinate
what are menders 3 laws
law of segregation
law of independent assortment
principle of dominance
law of segregation
yeah individual possesses two units of inheritance for each characteristic
although only one of These is transmitted to each offspring
law of independent assortment
genes at different loci segregate independently
principle of dominance
in pairs of alleles that are different
one allele will mask the effect of the other allele
human traits to show mendelian inheritance
hitchhikers thumb
tongue rolling
attached earlobes
human earwax
consistency of earwax
SNP in ABCC11 gene is the determinant of human earwax type
mendelian genetics in inherited diseases
sickle cell disease
huntingtons
different ways genetic condition can be inherited
mutations in single gene and usually inherited in one of several patterns
autosomal dominant
one mutated copy of gene is sufficient for person to be affected by disorder
can inherit from affected parent
huntington disease and Marfan syndrome inheritance
may result from new mutation in gene and our in people with no history of disorder
loci are on an autosome
not X or Y chromosome
dominance being relative based
on the function of the protein and nature of the allele
incomplete dominance
where allele has partial effect over other allele
co-dominance
where both alleles are apparent
Huntingdons disease
neurodegenerative disorder caused by an allele that codes for a dominant phenotype
offspring have 50% chance of inheriting allele and therefore disease from a parent with the disease
autosomal reessive
both copies of the gene in each cell have mutations
parents of individual with autosomal recessive condition each carry one copy of the mutated gene but they typically don’t show signs or symptoms
typically not seen in every generation in a family
examples of autosomal recessive conditions
cystic fibrosis
sickle cell
sickle cell disease
blood disorder
RBCs distorted into sickle or crescent shape leading to premature breakdown or getting stuck in small blood vessels leading to anaemia
autosomal recessive
heterozygous carriers of sickle cell disease
express partial phenotype
some blood cells are normal and some distorted
only sometimes have moderate symptoms
full sickle cell disease
individual must have 2 copies of alleles coding or recessive phenotype
must be homozygous recessive
x linked dominant
loci are on X chromosome
allele masks other allele on other chromosome
x linked dominant in males vs females
males only require one copy of the gene to cause the disorder, often more severe
females require one of the two copies is sufficient
x linked recessive
XX females allele is masked by other allele on other chromosome unless both alleles are mutant
XX female has one normal and one mutant
doesn’t normally show any phenotype
XY males always affected
