Topics: Chromosome, Gene, Genetics Pages: 7 (1518 words) Published: May 1, 2013
Know definitions of the words used for Meiosis, Mendel's work and Genetics

Dominant – expression that is always expressed when its gene

recessive - An expression that is expressed only when its allele is the only form of the gene present in the genotype.

incomplete dominance - Neither allele is dominant to the other, thus each is expressed in the heterozygous genotype producing an intermediate phenotype. EX. Red (RR) and White (R’R’) snapdragons produce pink (RR’).

epistasis - A condition in which one gene pair has the ability to mask or prevent the expression of another gene pair. EX. Coat color and pigment deposition in mice.

co-dominance - Inheritance characterized by full expression of both alleles in the heterozygote. Ex. Short HornCattle. Red (RR), Roan (RR’), White (R’R’)

homozygous – condition where both genes are the same (AA or aa)

heterozygous – condition where genes are different (Aa)

alleles – different forms of the same gene (Aa)

mutation – a change in the nucleotide sequence of an organism’s DNA or in the DNA or RNA of a virus

locus – location of the gene on the chromosome

gene - The unit of DNA along a chromosome that codes for a single characteristic, unit of dna that codes for a specific polypeptide

synapsis - Pairing of homologous chromosomes called

cross-over - The exchange or mixing of similar genetic material (genes) is called

chiasmata - There is a criss-crossing of the non-sister chromatids called

gene – unit of dna that codes for a specific polyeptide or characteristic

karyotype - A display of metaphase chromosomes in which homologues are paired together and photographed.

non-disjunction – an error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from eachother

pleiotrophy - The ability of a single gene pair to have multiple effects. EX. Gene for Sickle-cell Anemia.

Polyploidy – a chromosomal alteration in which the organism possesses more than 2 complete chromosome sets. It is the result of an accident of cell division

aneupliody – a chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number

monosomy – diploid cell that has only one copy of a particular chromosome instead of the normal two

trisomy – diploid cell that has three copies of a particular chromosome instead of the normal two

amneocentesis – a technique associated with prenatal diagnosis in which amniotic fluid is obtained by aspiration from a needle inserted into the uterus. The fluid and the fetal cells it contains are analyzed to detect certain genetic and congenital defects in the fetus.

chorionic villus sampling – a technique associated with prenatal diagnosis in which a small sample of the fetal portion of the placenta is removed for analysis to detect certain genetic and congenital defects in the fetus.

sex chromosomes – chromosomes involved in sex determination, in man these are the X and Y chromosomes oogenesis

spermatogenesis – continuous and pro-life production of mature sperm cells in the testes.

polygenic inheritance - A characteristic that is determined by the quantitative effect of multiple pair of genes.

duplication – an aberration in a chromosome structure due to fusion with a fragment of a homologous chromosome, such that a portion of a chromosome is duplicated

translocation – an aberration in chromosome structure resulting from attatchment of a chromosomal fragment to a non homologous chromosome. In a translocation a portion of a chromosome breaks and rejoins with a non-homologous chromosome. This type of abnormality can result in an increased number of genes in a gamete or can impact coordination of a metabolic path.

deletion - A portion of a chromosome is lost from the genome, thus these genes are not present in the gamete. The lose of genes from the genotype is serious and often...
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • Speech Essay
  • Essay about Inspirational Speech for school elections
  • Informative Speech Essay
  • Essay about Persuasive Speech
  • Speech to Entertain Essay
  • Persuasive Speech Outline Essay
  • Essay about Speech Script
  • Speech Prep Essay

Become a StudyMode Member

Sign Up - It's Free