- branch of biology that deals with inheritance
- ( what is passed on from one generation to the next )
visible traits, physical features
genetic make up of the person, not visible
using a specific example, explain how genotype gives rise to the phenotype of an individual.
- instructions of phenotype in genotype,
- - genetic make up has genetic code of phenotype
- different versions of a gene/same location, express same trait
Explain why there is an equal chance of getting either one of the alleles for a particular trait.
- - meiosis, genes shuffled by crossing over
- - independent assortment
" same " alleles that code for (express) the same trait
Alleles code for different traits
Define Dominant allele.
- represented by the first Capitalized letter of the dominant trait
- - express the trait, whether its in heterozygous/ homozygous
Define Recessive allele.
- - is represented by the first non- capitalized letter of the dominant trait
- - will express trait only if it's in a homozygous condition
a method of finding out the inheritance pattern of a trait between two single organisms
Define Dihybrid crosses
- is a cross between F1 offspring (first generation offspring) of two individuals that differ in two traits of particular interest. For example: RRyy/rrYY or RRYY/rryy parents result in F1 offspring that are heterozygous for both R and Y (RrYy).
- - A dihybrid cross is often used to test for dominant and recessive genes in two separate characteristics.
define incomplete dominance
2 alleles and neither one is dominant over another
whether an organism is homozygous or heterozygous for a certain condition
phenomenon where the effects of one gene are modified by one or several other genes
Define linked genes
- is a term which describes the tendency of certain loci or alleles
- to be inherited together. Genetic loci on the same chromosome are
- physically close to one another and tend to stay together during meiosis
what are linkage maps?
relative positions of genes on a chromosome
Explain how linkage maps are determined.
rate of cross over, how far apart genes are, independant assortment is not going to shuffle genes
what is sex-linked inheritance?
usually the inheritance of genes on the x chromosome
why men are more likely to have sex linked disorders then women?
size of the chromosomes, X is bigger and Y is smaller
- traits are a special case. They are controlled by genes on the sex
- chromosomes, X and Y. The female has two X chromosomes and the male has
- one X and one Y. Both males and females are equally likely to have a
- recessive allele on one X chromosome. However, if a female has a
- recessive allele, there's a good chance that the OTHER X chromosome will
- have a dominant allele, nullifying the effect of the recessive allele
- on the first X chromosome. But, a male does not have another X
- chromosome. So, if he has the recessive allele on his one X chromosome,
- he will have the trait. Period.
what 2 types of cells do mammals have?
cells with an active maternal X chromosome and cells with an active paternal X chromosome
what is the barr body?
A Barr body is the inactive X chromosome in a female somatic cell, or the inactive Z in a male, rendered inactive in a process called lyonization,
what is multiple allele inheritance?
more than 2 alleles code for the same trait
whats the difference between antigens and antibodies?
Antigens: substance or molecule that when introduced into the body triggers the production of an antibody by the immune system which will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader
Antibody:proteins, are used by the immune system to identify and neutralize foreign objects, such as bacteria and viruses
Explain why type O is a "universal donor".
Because it does not contain any "A" or "B" proteins. "O"- Negative would not contain the rhesus "Rh" factor either, further making it the universal donor.
O negative is the universal donor because there are absolutely no proteins on the RBCs, which means that anyone can receive that blood without suffering rejection. That is the same reason that people with O negative can only receive O negative.
what is Codominance?
- both alleles are visible in the phenotype
- - both individually expressed
Define incomplete dominance.
type of inheritance in which one allele for a specific trait is not completely dominant over the other allele. This results in a combined phenotype (expressed physical trait).
Why is blood type AB a "universal recipient"?
recieves any blood type becasue they have both A and B antigens
what happens duing incompatible blood transfusion?
the antibodies in your plasma will recognize the transfused (donor) blood as foreign and will attack and destroy the donor red blood cells, the RBC will clump together (aggutination) which causes kidney failure and liver failure and even death
what is Rh?
"Rhesus monkey " an antigen that can be present on the surface of the RBC
Explain the cause and preventative treatment for hemolytic disease of the newborn(HDN).
cause: The 1st pregnancy is fine, the placenta hides RBC of fetus from immune system so mother doesnt produce Rh antibodies, but at delivery the placenta tears and there is mixing of the 2 blood and mother gets exposed to Rh and antibodies produce but by that time baby is already delivered, but the 2nd pregnancy, the Rh antibodies will cuase agglutination(clump and stick together) b/c it was explosed to in first pregnancy
Treatment: give mother RhoGam -> anti Rh gamma globulin(protein) it is against Rh label
what is Pleiotropy?
one pair of alleles causes many changes in phenotype(expressions)
Explain why Ehlers Danlos Syndrome is a pleiotropic condition.
- -caused by a dominant allele
- - causes the collegen fibres to be too elastic
- - many symptoms, joints elastic(easy to dislocate), skin elastic, cant change shape of lens so cant see far
what is polygenic inheritance?
- when you have many pairs of allels/genes
- - wide range of particular phenotypes
Explain the reason for uneven pigmentation in the fur of the himalayan rabbit and siamese cat.
- -temperature drops in nose, ears, toes, so alleles get expressed (darker features)
- - the hairs stays dark but base of hair is white
- - allele -> pigment (melanin) "expressed" only if temperature drops lower than 37 degrees
Define pedigree analysis.
- study of family to figure out genotype of person
- -if dominant, a child that has the trait must have at least one parent also have the trait