Q) What are the main features of homologous chromosomes?
Main points | |
Key idea: | Inheritance of chromosomes (chrom) |
·Each member of a pair of homologous chrom is inherited fr either parent | |
Key idea: | Physical similarities |
· Same length & position of centromeres | |
Key idea: | Carry same genes but may not be identical alleles |
·Homologous chrom contain same genes (coding for the same characteristics) ·Ref to same order of gene loci aong length of chrom (or same corresponding position of each gene on either chrom) ·But may have diff alleles for each gene locus - hence, members of each pair of homologous chrom are not genetically identical | |
Key idea: | Behavior of homologous chromosomes during prophase I, meiosis |
·Each chrom condenses to form double structure consisting of 2 identical sis chromatids ·Pairing up of homologous chrom to form bivalents where chiasma or chiasmata may form leading to crossing over | |
Comments: (i) Visualize the answer with the aid of a labelled diagram (ii) Verbalize the answer + write down the main points w/o referring to the answer (use abbreviations) (iii) Read again within the next 24h & once more within 72h (do not spend more than 10min) (iv) Each member of a pair of homologous chromosome is also known as a homologue (v) Homologous chromosomes have the same sequence of gene loci. They may have the same alleles in certain gene loci but different alleles in other gene loci. Hence, they are genetically different since the combination of alleles in the homologous chromosomes is different from each other. | |
No comments:
Post a Comment