vocabulary #2

Abortion: premature spontaneous expulsion of the fetus from uterus.

aneuploidy: having one more or one less chromosome relative to the parental chromosome number.

autosome: any chrosome of a time that is the same in females a

nd males of the specie.

Crossing over:interaction in which non-sister chromatids of a pair of homologous chromosomes break at corresponding sites.

Deletion: loss of a segment from a chromosome.

Diseas: when difenses aren't mobilized fast enought.

Double-blind study: different investigators independently collect, then compare data.

duplication:gene sequence repeated several to may hundrededs or thousan of times.

genetic abnormality:a rare or less common version of a heritable trait.

genetic disoder: any inherited condition that cause mild to severe medical problems.

genetic recombination:result of any process that puts new genetic information into a DNA molecules.

Homologous Chromoseome: one of a pair of chromosomes identicaly in size,shape, and gene sequence.

in-vitro fertilization: conception outside the body.

independent assortmen: Mendelian theory that by the end of meiosis, each pair of homologous chromosomes are stored before shipment to gamets independently of how the other pairs were sorted.

inversion: part of the chromosome that became oriented in reverse.

karyotype: preparation of metaphase chromosome sorted by lenght.

Linkage group: all genes of a chromosome.

mosaicism: cells of same type express genes differently.

Non-disjunction: failure of sister chromatids or pair of homologous chromosomes to separate during mitosis or meiosis.

polyploidy: having three or more of each type of chromosomes in the nucleus of a eukaryotc cell.

reciprocal cross: a paired of cross.

sex chromosome:a chromosome with genes that affect sexual trait.

syndrome:a set of symptoms that may not individually be a telling clue but collectively characterize a genetic disorder or disease.

translocation: movement of a stretch of DNA to a new chromosomal location with no molecular loss.

X & Y chromosome: Are types of sex chromosomes. An XX mamalian embryo becomes female; and a XY embryo becomes male.

chapter 11- Pattern of Inheritance

1.allele: One of two or more molecular forms of a gene that arise by mutation and code for different versions of the same trait.

2.codominance: In heterozygotes, simultaneous expression of a pair of onidentical alleles that specify different phenotypes.

3.continuous variation: Of a population, a more or less continuous range of small differences in a given trait among its individuals.

4.dihybrid cross: An intercross between two F1 heterozygotes that are identical for two gene loci; the dihybrids are offspring of parents that bred true for different versions of two traits.

5.epistasis: Interaction among the products of two or more gene pairs.

6.F1: The offspring of aninitial genetic cross.

7.F2: The offspring of parents who are the first filial generation from a genetic cross.

8.gene: Unit of information for a heritable trait, passed from parents to offspring.

9.genotype: Genetic constitution of an individual; a single gene pair or the sum total of an individual's genes.

10.heterozygous: Having a pair of nonidentical alleles at a gene locus.

11.homozygous dominant: Having a pair of dominant alleles at a gene locus.

12.homozygous recessive: Having a pair of recessive alleles at a gene locus.

13.hybrid: offspring of a genetic cross,offspring having a pair of nonidentical alleles for a trait.

14.incomplete dominance:Condition in which one allele of a pair is not fully dominant; a heterozygous phenotype somewhere between both homozygous phenotypes emerges.

15.independent assortment: Mendelian theory that by the end of meiosis, each pair of homologous chromosomes are sorted before shipment to gametes independently of how the other pairs were sorted. Late

r modified to account for the disruptive effect of crossing over on linkages.

16.monohybrid cross: Intercross between two F1 heterozygotes that are identical for one gene locus; offspring of two parents that breed true for different for

ms of a trait. 17.multiple allele system: Three or more slightly different molecular forms of a gene that occur among individuals of a population.

18.phenotype: Observable trait or traits of an individual that arise from gene interactions and gene-environment interactions.

19.pleiotropy: Positive or negative effects on two or more traits owing to expression of alleles at a single gene locus. Effects may or may not emerge at the same time.

20.probability: The chance that each outcome of a given event will occur is proportional to the number of ways the outcome can be reached.

21.Punnett-square: method Construction of a simple diagram as a way to predict probable outcomes of a genetic cross.

22.segregation: Mendelian theory. Sexually reproducing organisms inherit pairs of genes, the two genes of each pair are separated from each other at meiosis, and they end up in separate gametes.

23.testcross: Experimental cross to determine whether an individual of unknown genotype that shows dominance for a trait is either homozygous dominant or heterozygous.

24.true-breeding lineage: Of sexually reproducing species, a lineage in which only one version of a trait appears over the generations in all parents and their offspring.

Chapter 11