Commonly used genetic terms

Question 1

allele

Answer 1

one member of a pair or series of genes, one from mother one from father (specific variation of gene)

Question 2

homozygous

Answer 2

if member of gene pair are identical (same gene product)

Question 3

heterozygous

Answer 3

having 2 diff alleles of a particular gene

Question 4

genotype

Answer 4

genetic composition of a person

Question 5

phenotype

Answer 5

is the observable expression of a genotype in terms of physical and biochemical traits

Question 6

dominant trait

Answer 6

trait is phenotypically seen in the heterozygote

Question 7

recessive traint

Answer 7

trait is phenotypically seen ONLY in homozygote

Question 8

codominance

Answer 8

when both alleles of a gene pair are phenotypically seen in the heterozygote

Question 9

example of codominance

Answer 9

blood group inheritance (AO, BO, AB)

Question 10

polymorphism

Answer 10

one or more normal allele (alternate forms) at same locus (specific location) within a gene pool
Normal variations in human gene that account for individual differences in physical traits behaviors and disease susceptibility (SNPs)

Question 11

gene mutation

Answer 11

biochemical event such as a nucleotide change, deletion, or insertion that produces a new allele for a particular gene

Question 12

reduced penetrance

Answer 12

when person inherits dominate mutant gene but fails to exhibit that associated phenotype

Question 13

variable expressivity

Answer 13

autosomal dominate disorders can be epxressed differently in people who carry mutant gene

Question 14

aneuploidy

Answer 14

having an abnormal number of chromosomes

Question 15

monosomy

Answer 15

refers to the presence of only one member of a chromosome pair- defects associated with this are sever and often cause miscarriage

Question 16

polysomy

Answer 16

presence of more than 2 chromosomes to a set occur when a germ cell (egg or sperm) containing more than 23 chromosomes is involved in conception