Genetics Crossword

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Across
  1. 2. over — The exchange of genetic material between nonsister chromatids of homologous chromosomes during prophase I of meiosis; produces recombinant chromatids and increases genetic diversity.
  2. 4. A type of cell division that reduces the chromosome number by half to produce haploid gametes; includes two successive divisions (Meiosis I and Meiosis II) and creates genetic variation through processes such as crossing over and independent assortment.
  3. 6. — A chromosome or chromatid that contains a new combination of alleles produced by crossing over during meiosis.
  4. 9. (n) — A cell that contains a single set of chromosomes, as in gametes (sperm and egg); in humans, haploid number is 23.
  5. 11. — A change in the DNA sequence that can occur as substitutions, insertions, deletions, or larger chromosomal alterations; mutations may be silent, harmful, or beneficial, and their effects depend on type and location.
  6. 12. — An organized visual profile of an individual’s chromosomes arranged by size and shape (usually in homologous pairs); used to detect chromosomal abnormalities such as trisomy 21 (Down syndrome).
  7. 13. — A pattern of inheritance in which two different alleles are both fully expressed in the heterozygote, producing a phenotype that shows both traits simultaneously (e.g., AB blood type or black-lace angelfish represented by BL).
  8. 14. — One of the two identical copies of a replicated chromosome, joined at the centromere until they separate during cell division.
  9. 15. / Recessive — Terms describing allele interactions: a dominant allele masks the expression of a recessive allele in a heterozygote (e.g., E is dominant to e). (Tier 2–3 pair treated together because they are closely linked concepts.)
Down
  1. 1. — An alternative form of a gene found at the same locus on homologous chromosomes; different alleles can produce variations in a trait (e.g., E vs. e for earlobe type).
  2. 3. — A mature reproductive cell (sperm or egg) that is haploid and can fuse with another gamete during fertilization to form a zygote.
  3. 5. mutation — A mutation caused by insertions or deletions (not in multiples of three nucleotides) that shifts the reading frame of the mRNA codons, typically altering every downstream amino acid and often producing a nonfunctional protein.
  4. 7. assortment — The random orientation and separation of different homologous chromosome pairs during meiosis I, which leads to gametes with different combinations of chromosomes and thus increases variation.
  5. 8. chromosomes — A pair of chromosomes (one from each parent) that carry genes for the same traits in the same order but may have different alleles.
  6. 10. (2n) — A cell or organism that has two complete sets of chromosomes (one from each parent); typical of most body (somatic) cells in humans (46 chromosomes).