Chapter 14 & 15 Flashcards
what is incomplete dominance and co-dominance. Provide examples of each.
- Incomplete dominance: neither allele is completely dominant, intermediate phenotype
ex: snapdragons (red x white) = pink - codominance: two alleles affect the phenotype in separate distinguishable ways
ex: blood type AB
locus
Physical location of a gene on chromosome
true breeding
-describes organisms that produce offsprings identical to themselves
- true breeding is always homozygous
F1 generation
offsprings that are outcomes of the parent generation
F2 generation
outcome of F1 generations when they procreate and reproduce
what is Mendel’s 1st law?
-law of segregation: two alleles coding for the same trait separate during gamete formation, we see this in mitosis and in meiosis 1.
-we usually see this in monohybrid crosses
what is Mendel’s 2nd law?
-law of independent assortment: alleles of different traits are distributed to sex cells independently; we see this in meiosis II
-we usually see this in dihybrid crosses
what is pleiotropy?
-the ability of one gene affecting more than one phenotype trait
ex: sickle-cell anemia; it could cause blindness, liver failure, and/ or heart attacks.
what is an autosome?
-a body chromosome
- chromosomes from 1 to 22 are autosomes
what is a sex-chromosome?
- X or Y chromosome
- the 23rd pair of chromosomes
how is sex determined in humans?
- the X-Y system
-the genotype of a man is XY, the genotype of a women is XX.
what is a sex-linked gene?
-it’s a gene determined by its presence on the sex chromosome
-it is mainly carried on the x chromosome
ex: colorblindness (x-linked recessive gene)
Are sex-linked genes more likely to show up in males or females?
Males because since they have two x chromosomes in their genotype, they are more likely to be x-linked recessive
