Genetics Flashcards
Definition : Homozygous
Having matching alleles on homologous chromosomes
Definition : Heterozygous
Having two different alleles on homologous chromosomes
Homologous pair
Meaning the two alleles are the same. Eg (RR) or (rr)
Heterozygous pair
Meaning the two alleles are different. Eg (Rr)
Alleles
Different forms of the same gene, located at the same point of homologous chromosomes
Dominant trait
The trait that is observed in the outward appearance of the individual. ( represented as the capital letter (R) )
Recessive trait
The trait that remains hidden. ( represented as a lower case letter (r) )
Genotype
Genotypes are the actual genetic information carried by an individual
Phenotype
Phenotypes are the observable characteristics or traits of the individual.
Dominant inheritance
Traits that are shown
Recessive inheritance
Traits that are hidden unless there is no dominant trait
Sex determination
MALE (XY) - FEMALE (XX). Eggs produced by a female will have one X chromosome
Half the male sperm will carry an X chromosome and the other half a Y chromosome.
Sex linkage
Sex linked genes are present on one of the chromosomes that is also responsible for determination of sex
Mutations
Mistakes can happen as DNA is copied. The base sequence is changed and mistakes occur in the manufacture of proteins. Mutations may happen by chance or result from damage to a stand of DNA
Chromosomal abnormalities
Sometimes mistakes happen during meiosis, when the sex cells are being produced. Eg. if the chromatids fail to separate a child will be born with an extra chromosome.
