title: Climatic influence on the reproductive characteristics of Japanese males.
abstract: We previously performed a survey of the sperm characteristics of the partners of pregnant women in four cities in Japan. In the present study, we analyzed the sperm characteristics of these subjects and the correlations between these sperm characteristics and climatic changes or Y chromosome haplogroups. Our results showed that more haplogroup D2a1 males than O2b1 males were born in the first half of the year (January to June), whereas more O2b1 males were born in the last half of the year (July to December) (P<0.05). This was agreed and correlated with the seasonal variations in their mean sperm concentrations. The haplogroup C, D* and D2a1 males displayed lower sperm concentrations from March to May, followed by an increase in their sperm concentrations starting in June or July, while the O2b1 males displayed higher sperm concentrations in the first half of the year followed by a sudden decrease from July to August (P<0.05). We hypothesize that the Japanese climate has different effects on the sperm characteristics and reproductive seasonality of males from different lineages; and therefore, has influenced the modern population of Japan.
authors.affiliation: Department of Human Genetics and Public Health, Graduate School of Medical Science, University of Tokushima, Tokushima, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nakahori
authors.forename: Youichi
authors.initials: Y
authors.lastname: Sato
authors.forename: Ashraf A
authors.initials: AA
authors.lastname: Ewis
authors.forename: Teruaki
authors.initials: T
authors.lastname: Iwamoto
authors.forename: Toshikatsu
authors.initials: T
authors.lastname: Shinka
authors.forename: Shiari
authors.initials: S
authors.lastname: Nozawa
authors.forename: Miki
authors.initials: M
authors.lastname: Yoshiike
authors.forename: Xin-Jun
authors.initials: XJ
authors.lastname: Yang
authors.forename: Masako
authors.initials: M
authors.lastname: Sei
authors.forename: Mikio
authors.initials: M
authors.lastname: Namiki
authors.forename: Eitetsu
authors.initials: E
authors.lastname: Kou
authors.forename: Naoki
authors.initials: N
authors.lastname: Ito
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Komatsu
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Matsumiya
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nakagome
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics*; D041322:Chromosomes, Human, Y; D002980:Climate; D059647:Gene-Environment Interaction; D056084:Genetic Fitness; D005819:Genetic Markers; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D012098:Reproduction / Q000235:genetics*; D013076:Sperm Count; D055815:Young Adult
chemical_list: D005819:Genetic Markers