Bio 1108 Exam 8
Prophase 1: Non-Disjunction
- abnormal separation of chromosomes - if fusion of three copies, then its trisome (trisomy-21 is down syndrome, edward-18, patal syndrome-18) - if fusion of one, then its aneuploidy, xo instead of xy
incomplete dominance
- blend of traits - a white flower (AwAw) mates with red flower (ArAr) to get AwAr and a pink flower
Codominant
- both traits are present but not blended - black and white cows make a roan cow thats spotty
genetic probability
- chance of allele genotype frequency
Mendel law of segregation
- egg and sperm allele pair separate and randomly unite during fertilization - dihybrid cross 9/16, 3/16, 3/16, 1/16, ratio shows traits are independent
crossover frequency
- genes do not assort independently - higher percentage means more crossing over and farther apart on the chromosomes
Autosomal
- non sex chromosomes (1-22 pairs)
Pleiotropy
- one gene can affect multiple traits - mutation can cause more than one health problem
Meiosis
- reduction division - cell divides twice to produce gamete
Epistatis
- regulatory genes that affect nearby genes - on/off switch
Sex Linkage (X-linked traits)
-trait is one the x chromie (mostly in males) - the presence of a gene on a sex chromosome
Pedigree
circle - female square - male shaded - affected by the trait
Prophase 1: Synapsis
four homologous chromosomes come together to form tetrad
Test Cross
the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the parent genotype
sex-linked chromosomes
traits that are carried on the the x or y chromosome - sry is what makes testosterone
Recessive Allele inheritance
two unaffected parents have two children one isn't affected and one is
Prophase 1: Crossing Over
arms cross over and genes move on the chromie, this increases genetic variation
GD: Color Blind
sex link
GD: Hemophilia
sex linked
GD: Achondroplasia
Autosomal Domminant
GD: Cystic Fibrosis
Autosomal Recessive
GD: Tay-Sachs
Autosomal Recessive
GD: Huntington Disease
Autosomal Recessive- post reproductive
Dominant Allele Inheritance
affected parents have children, one is affected and one isnt
mendell law of dominance
inheritance factors, one dominant gene overshadows recessive