USABO - Genetics
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1. homologous Chromosomes that have the same sequence of genes and the same structure
chromosomes
2. chiasmata X-shaped regions where crossing over occurred.
3. cohesins Proteins that hold sister chromatids together
4. crossing over Process in which homologous chromosomes exchange portions of their chro-
matids during meiosis.
5. synaptonemal A zipper-like protein structure that causes replicated homologs to become phys-
complex ically connected during prophase of meiosis I; sets the stage for crossing over.
6. synapsis the fusion of chromosome pairs at the start of meiosis.
7. P generation Parental generation, the first two individuals that mate in a genetic cross
8. F1 generation the first generation of offspring obtained from an experimental cross of two
organisms
9. F2 generation Offspring resulting from interbreeding of the hybrid F1 generation.
10. Law of Segrega- Mendel's law that states that the pairs of homologous chromosomes separate in
tion meiosis so that only one chromosome from each pair is present in each gamete
11. incomplete dom- Situation in which one allele is not completely dominant over another allele
inance
12. Codominance A condition in which both alleles for a gene are fully expressed
13. Pleiotropy The ability of a single gene to have multiple effects.
14. epistatis gene at one locus on the chromosome alters the phenotypic expression of a gene
at different locus
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15. polygenic inheri- combined effect of two or more genes on a single character
tance
16. cystic fibrosis A genetic disorder that is present at birth and affects both the respiratory and
digestive systems.
17. amniocentesis needle puncture of the amniotic sac to withdraw amniotic fluid for analysis (15
week of pregnancy)
18. chronic villus A technique of prenatal diagnosis in which a small sample of the fetal portion of
sampling the placenta is removed from the cervix and analyzed to detect certain genetic and
congenital defects in the fetus. (10th week of pregnancy) way faster
19. X-Y system of sex Occurs in mammals(XY represents male, XX represents female)
determination
20. X-0 system of sex Grasshoppers, females have two sex chromosomes, females have two
determination
21. Z-W system The sex chromosome inheritance system in species in which the male is homoga-
metic (ZZ) and the female is heterogametic (ZW). (birds, fishes, insects)
22. haplo diploid sys- A sex determination system in most species of bees and ants in which there are
tem no sex chromosomes. Females develop from fertilized eggs (diploid) and males
develop from unfertilized eggs (haploid).
23. X inactivation one of two X chromosomes is randomly inactivated and remains coiled as a Barr
body
24. recombinants offspring with non parental phenotypes
(recombinant
types)
25.
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recombinant fre- the proportion of offspring of a genetic cross that have phenotypes different
quency from the parental phenotypes due to crossing over between linked genes during
gamete formation
26. linked genes Genes located on the same chromosome that tend to be inherited together in
genetic crosses.
27. Sturtevant This person developed a way to use crossover data to map gene loci. He hypothe-
sized that the farther apart two genes are on a chromosome, the more points there
are between them where crossing over can occur (which is not entirely accurate)
28. linkage map A genetic map based on the frequencies of recombination between markers
during crossing over of homologous chromosomes.
29. Nondisjunction Error in meiosis in which homologous chromosomes fail to separate.
30. Aneuploidy Abnormal number of chromosomes.
31. Polyploidy condition in which an organism has extra sets of chromosomes
32. genomic imprint- a phenomenon in which expression of an allele in offspring depends on whether
ing the allele is inherited from the male or female parent
33. Chromosomal a graphic representation of the positions of genes on chromosomes; obtained
map by observation of chromosome bands or by determing the degree of linkage
between genes
34. origin of replica- Site where the replication of a DNA molecule begins, consisting of a specific
tion sequence of nucleotides.
35. replication fork A Y-shaped region on a replicating DNA molecule where new strands are growing.
36. Helicase An enzyme that untwists the double helix of DNA at the replication forks.
37. bind to and stabilize single-stranded DNA
Study online at https://quizlet.com/_ebutry
1. homologous Chromosomes that have the same sequence of genes and the same structure
chromosomes
2. chiasmata X-shaped regions where crossing over occurred.
3. cohesins Proteins that hold sister chromatids together
4. crossing over Process in which homologous chromosomes exchange portions of their chro-
matids during meiosis.
5. synaptonemal A zipper-like protein structure that causes replicated homologs to become phys-
complex ically connected during prophase of meiosis I; sets the stage for crossing over.
6. synapsis the fusion of chromosome pairs at the start of meiosis.
7. P generation Parental generation, the first two individuals that mate in a genetic cross
8. F1 generation the first generation of offspring obtained from an experimental cross of two
organisms
9. F2 generation Offspring resulting from interbreeding of the hybrid F1 generation.
10. Law of Segrega- Mendel's law that states that the pairs of homologous chromosomes separate in
tion meiosis so that only one chromosome from each pair is present in each gamete
11. incomplete dom- Situation in which one allele is not completely dominant over another allele
inance
12. Codominance A condition in which both alleles for a gene are fully expressed
13. Pleiotropy The ability of a single gene to have multiple effects.
14. epistatis gene at one locus on the chromosome alters the phenotypic expression of a gene
at different locus
, USABO - Genetics
Study online at https://quizlet.com/_ebutry
15. polygenic inheri- combined effect of two or more genes on a single character
tance
16. cystic fibrosis A genetic disorder that is present at birth and affects both the respiratory and
digestive systems.
17. amniocentesis needle puncture of the amniotic sac to withdraw amniotic fluid for analysis (15
week of pregnancy)
18. chronic villus A technique of prenatal diagnosis in which a small sample of the fetal portion of
sampling the placenta is removed from the cervix and analyzed to detect certain genetic and
congenital defects in the fetus. (10th week of pregnancy) way faster
19. X-Y system of sex Occurs in mammals(XY represents male, XX represents female)
determination
20. X-0 system of sex Grasshoppers, females have two sex chromosomes, females have two
determination
21. Z-W system The sex chromosome inheritance system in species in which the male is homoga-
metic (ZZ) and the female is heterogametic (ZW). (birds, fishes, insects)
22. haplo diploid sys- A sex determination system in most species of bees and ants in which there are
tem no sex chromosomes. Females develop from fertilized eggs (diploid) and males
develop from unfertilized eggs (haploid).
23. X inactivation one of two X chromosomes is randomly inactivated and remains coiled as a Barr
body
24. recombinants offspring with non parental phenotypes
(recombinant
types)
25.
, USABO - Genetics
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recombinant fre- the proportion of offspring of a genetic cross that have phenotypes different
quency from the parental phenotypes due to crossing over between linked genes during
gamete formation
26. linked genes Genes located on the same chromosome that tend to be inherited together in
genetic crosses.
27. Sturtevant This person developed a way to use crossover data to map gene loci. He hypothe-
sized that the farther apart two genes are on a chromosome, the more points there
are between them where crossing over can occur (which is not entirely accurate)
28. linkage map A genetic map based on the frequencies of recombination between markers
during crossing over of homologous chromosomes.
29. Nondisjunction Error in meiosis in which homologous chromosomes fail to separate.
30. Aneuploidy Abnormal number of chromosomes.
31. Polyploidy condition in which an organism has extra sets of chromosomes
32. genomic imprint- a phenomenon in which expression of an allele in offspring depends on whether
ing the allele is inherited from the male or female parent
33. Chromosomal a graphic representation of the positions of genes on chromosomes; obtained
map by observation of chromosome bands or by determing the degree of linkage
between genes
34. origin of replica- Site where the replication of a DNA molecule begins, consisting of a specific
tion sequence of nucleotides.
35. replication fork A Y-shaped region on a replicating DNA molecule where new strands are growing.
36. Helicase An enzyme that untwists the double helix of DNA at the replication forks.
37. bind to and stabilize single-stranded DNA
