Terms in this set (37)
A segment of DNA on a chromosome that codes for a specific trait
A variation of a single gene that controls an inherited characteristic.
An organism that has two identical alleles for a trait
An organism that has two different alleles for a trait
An organism's genetic makeup, or allele combinations.
An organism's physical appearance, or visible traits.
Describes a trait that covers over, or dominates, another form of that trait.
An allele that is masked when a dominant allele is present
Passing of traits from parents to offspring
law of independent assortment
states that genes for different traits are separated independently during the formation of gametes. (traits are not "linked")
law of segregation
states that the pairs of homologous chromosomes separate in meiosis so that only one chromosome from each pair is present in each gamete
law of dominance
states the dominant trait is always expressed over the recessive trait if its allele is present.
A pattern of inheritance in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable.
A pattern of inheritance in which two alleles, are neither dominant nor recessive. The resulting offspring have a phenotype that is a blending of the parental traits. (ex. pink flowers)
A pattern of inheritance in which both alleles for a gene are fully expressed. (ex. roan cows)
Pair of chromosomes that are the same size, same shape and same genes.
Replicated forms of a chromosome (identical) joined together by the centromere and eventually separated during mitosis or meiosis II.
the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes
Process in which homologous chromosomes exchange portions of their chromatids during meiosis.
a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell ( the production of gametes)
a type of cell division that results in two daughter cells each with the same number of chromosomes of the parent cell
Pairing of homologous chromosomes
The separation of homologous chromosomes during meiosis
structure containing 4 chromatids that forms during meiosis
A picture of all the chromosomes in a cell arranged in pairs
A reproductive process that involves only one parent, no fusion of gametes and produces offspring that are identical to the parent.
A reproductive process that involves two parents that combine their genetic material to produce a new organism, (fusion of gametes) which differs from both parents
containing two complete sets of chromosomes, one from each parent.
having a single set of unpaired chromosomes
production of 4 viable motile sperm within the testes. Occurs constantly (~1500 per second) slightly below body temperature
production of 1 viable ovum and 3 polar bodies within the ovaries. Occurs cyclicly (once a month) at body temperature
Fusion of an egg and sperm cell
a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.
Sources of genetic variation
crossing over, independent assortment, random fertilization, & mutations
Testing to find the genotype of a dominant phenotypic individual (AA or Aa) by crossing it with a known homozygous recessive (aa)
Chromosomal abnormality consisting of the absence of one chromosome from the normal diploid number
a condition in which an extra copy of a chromosome is present in the cell nuclei, causing developmental abnormalities.