Topic 6 - Heredity (Inheritance) Flashcards
Inheritance
- transfer of genetically determined characteristics from one generation to the next
genetics
study of inheritance
23 homologous pairs
how many is ___________
how many is ______
- 22 homologous pairs autosomal - somatic characteristics
- 1 pair sex chromosomes
XY
male or female
Male
XX
male or female?
Female
alleles
genes occupying the same locus on homologous chromoosmes
alleles may be:
homozygous or heterozygous
homozygous
- same allele of a particular gene on homologous chromosomes
- e.g. both alleles express the same version of a trait
- e.g. blonde hair (bb), black hair (Bb)
heterozygous
- different alleles of the same gene
- e.g. alleles code for different expressions of the same trait
- e.g. Bb
catalogue of a person’s genes (genetic makeup)
e.g. Bb
Genotype
expression of genotype (genes) to give observable characteristics
e.g. black hair
Phenotype
- expressed in phenotype regardless of other allele
- BB or Bb: ________ expressed
- e.g. black hair
dominant allele
B
- expressed in phenotyp only if present on both alleles
- bb
- blonde hair
recessive allele
b
- determines probability of inheritance
- predicts offspring genotype and phenotype
- hair colour trait BB x bb
punnet square
- hemophilia
- colour-blindness
- duchenne’s muscular dystrophy
all due to recessive alleles on the X chromosome
sex-linked inheritance
sex-linked inheritance
XY =
not truly homologous
if gene is X-linked its expression is not masked because there is no corresponding allele on Y chromosome
XX = Homologous
:)
sex-linked
is colour blindness a dominant or recessive trait?
recessive
