genetics test Flashcards
(17 cards)
The study of heredity, how traits (characteristics) are passed down from one generation to the next
Genetics
sequence of DNA that codes for a protein & thus determines a trait
Gene
A picture or display of all the pairs of chromosomes in numerical order based on size & shape
Karyotype
Chromosomes that pair up and have the same genes, are the same size and shape.
One from mother & one from father.
Homologous chromosomes
Contain genes for all traits except for sex
Chromosome pairs 1-22
Autosome
Chromosome pair #23
XX – 2X’s will make female
XY – will make male
Sex Chromosomes
Different forms of the same gene for a specific trait.
Ex. Trait – eye color
Alleles – blue, brown, green
Alleles
An allele expressed with another recessive.
Written as a small letter.
Recessive
An allele that is expressed over a recessive
Written as a capital letter
Dominant
Outward (physical) appearance of the alleles
Ex. Blue eyes, tallness, being colorblind
Lots of misconceptions about dominant & recessive
Phenotype
The genetic makeup (gene combination) of an organism
Genotype
Having 2 identical alleles for a specific trait
Purebred
Can be dominant or recessive
Homozygous
Having 2 different alleles for a specific trait
Hybrid or carrier
Heterozygous
Two different alleles of the same trait are fully expressed Ex: Human blood types - A, B, AB, O Alleles: IA, IB, i IA & IB - i - recessive (ii=type O blood)
Codominance
Two different alleles of same trait combine (BLEND) to form a new expression of alleles
Ex: Colors in flowers, red + whitepink
Incomplete Dominance
Trait produced from many alleles on more than one chromosome
Ex. Hair color, skin color, eye color, height
Polygenic traits
Traits carried on the sex chromosomes (mostly the x chromosome)
Sex linked traits
