Mendel's law Flashcards
what are mendel’s 2 laws
1) law of segregation 2) law of independant assortement
what are the names of generations
1) parental
2) first filial
2) second filial
what is a monohybrid cross
cross fertilizitation between 2 monohybrid organisms (monohybrid = heterozygous for 1 sepecific trait)
cross between 2 individuels who are heterozygous at 1 locus, only compares 1 trait
how to perform a test cross
- cross mystery parent with homozygous recessive parent, because phenotype does not always reveal genotype (can be heterozygous or homozygous dominant)
- if it is an all dominant offspring, YY
- if mixed , Yy
what is a dihybrid cross
-cross-fertilization between 2 dyhibrid organisms (2 organisms that are heterozygous for 2 specific traits)
what is the rule of multiplication
probability for more then 2 events to occur together is calclulated by multiplying the chances each event occurs alone
what is polygentic inheritence
a signle phenotypic trait affected by multiple genes
what is pleiotropy
a single gene that has an effect on multiple genetic traits
what is the law of segregation
2 alleles of same gene will end of in different gametes after meiosis
what is the law of independant assortement
alleles of 2 different genes get sorted into gametes indep. of each other (homologous chromosomes randomly line up in metaphase 1 and 2)
are sex chromosomes truly homologous?
No, but they do pair up during meiosis and behave like homologous (posseses small regions where they are homologous)
what are some sex linked characteristics
- hemophilia (lack of blood coagulation)
- color blindness (
what is dosage compensation (x inactivation)
- since woman have 2 xx chromosomes, dosage compensation works to make the doses equal
- inactivation of 1 or part of the x chromosome
what is a barr body
dense, metabolically inactive x chromosome, to avoid over-expression of the x genes in females
what is polyploidy
presence of multiple sets of chromosomes (more then n , ie, more then diploid) , does not cause abnormalities (3n, 4n), more then 1 pair of homologous chromosomes
what is Aneuploidy
abnormalities caused by too many or too little chromosomes
what is nondisjunction
- results in aneuploidy
- abnormal number of chromosomes
- can occur in autosomes and sex chromosomes
what is disomy
normal
what is trisomy
extra chromosomes (3 of one kind)
what is monosomy
lack one member of a pair of chromosomes
what is Turner’s syndrome in woman
- XO (lack of Y)
- girls lack normal ovaries
- may have male characteristics (lack of breasts)
what is Klinefelter syndrome
- YXX
- male, possess y chromosome
- may have breasts and other male charateristics
- can be alleviated with long term treatment
what are the types of abnormal chromosome structures
- Deletion
- Duplication
- Inversion
- reciprocal translocation
what is the relation between genes and the environment
- the genes set the limits, the environment molds the phenotyp, within gene’s limits
