Extension of mendels laws #2 Flashcards
complete dominance
when the dominant allele completely masks the recessive one
examples of complete dominance
~widows peck
~Hitchhikers thumb
~free ear lobe
~rolled tongue
incomplete dominance
when one allele is unable to completely mask the other, thus resulting in a third phenotype
examples of incomplete dominance?
~hair texture
~skin color
co-dominance
when contributions of both alleles are visible in the phenotype
example of Co-dominance
blood type
multiple alleles
while an individual carries only 2 alleles, there can be many alleles circulating in the population
explain blood type determination
the ABO blood type is controlled by a single gene located on the q arm of chromosome 9.
It has 3 types of alleles: IA, i, IB
This encodes for the glycosyl-transferase enzyme
if you have an IA allele what is expressed?
the glycosyltransferase allows the RBC to express the A carbohydrates
if you have i blood type what is expressed?
no carbohydrates
what antibodies do we make?
we make antibodies against the carbohydrates not present in the organism
AB is the ? O is the ?
universal acceptor
universal donor
what other factor other than ABO affects blood type
the Rh blood group system
Rh blood group system
5 antigens D,C,c,E,e are available. The Rh+ and Rh- refers only to the D antigen
A person with Rh- can donate to Rh+. but not the other way around
Erythroblastosis fetalis
is a hemolytic disease of the newborn, when the antibodies of the mother determine the lysis of fetal red cells causing anemia, hypoalbuminea, high output heart failure, Can be trated by an IV intrauterine blood transfusion
penetrance?
the proportion of individuals carrying a specific allele/genotype that express the associated phenotype
complete penetrance
when 100% of individuals carrying the genotype express the phenotype
expressivity
variations in a phenotype among individuals carrying a specific genotype
pleiotropy
when one gene influences multiple apparently unrelated phenotypic traits, Cystic fibrosis
cytogenetics. What are the 2 kinds?
is a branch of genetics that studies the structure and function of chromosomes.
Classic cytogenetics: analysis of banding chromosomes
Molecular cytogenetics: analysis performed at the molecular level: FISH, CGH
karyotype
a picture of the chromosomes. They show the number and morphology . It is taken during metaphase of mitosis
n means what?
means Homologs, as in the pairs of chromosomes
heterosomes
sex chromosome
autosomes
all non sex chromosomes
what did fleming observe in 1880
chromosomes during mitosis
Sutton(grasshoppers) and boveri (sea urchins) in 1902-1903 did what?
independently form each other they proposed the chromosome theory of inheritance
the Sutton-boveri theory was debated till 1915, when - happened?
Thomas morgan provided his evidence based on drosophila
explain studies on human karyotypes in 1950
Giemsa stained chromosomes and squashed between cover + slide. thought the 2n was 48
giemsa
named after gustav giemsa, is specific for the phosphate groups of DNA
when was 2n=46 established?
in 1956, by using a solution of colchicine : an alkaloid able to inhibit mitosis by disrupting microtubule polymerization
when was the first obsevationthat diseases can devie from abberant # of chromosomes?
1959, a trisomy, Down syndrome
the Denver conference on 1960 resulted in 4 statements
~ chromosomes are grouped in 7 sets of similarly sized and shaped chromosomes
~pairs are #red 1-22 (longest to smallest)
~sexual chromosomes X, Y
~the 7 groups were A-G
when were banding techniques established?
1970
when was he beginning of molecular cytogenetics?
1980
